Apparatus for deflecting light device for scanning light device for reading information and device for stereoscopic display

ABSTRACT

An apparatus for deflecting light of the present invention comprises: (a) at least one pair of transference electrodes arranged facing one another; (b) a drive circuit which applies a voltage among the transference electrodes; and (c) a liquid crystal which is inserted among the transference electrodes, and whose parallel stripes that function as a diffraction grating when the voltage is applied among the transference electrodes are produced at a pitch corresponding to the applied voltage. The light can be scanned if a diffracted light by the apparatus for deflecting light is converted into a scanning light and a voltage value is changed temporally to apply the voltage among the transference electrodes. In a device for reading information, the scanning light is reflected in a bar code and the reflected light is detected by an apparatus for detecting light. In a device for stereoscopic display of the present invention, the apparatus for deflecting light is used as beam deflection means for deflecting the light beamed from a picture element which organizes the pictures of the picture display means.

This application is a divisional of U.S. application Ser. No. 08/405,602filed Mar. 17, 1995, now U.S. Pat. No. 5,815,222.

BACKGROUND OF THE INVENTION

In recent years, a commodity management by POS system (point of salessystem) has been executed very actively. The optical device for readinginformation like a bar code reader has been used for the POS system.

Namely, such data processing as an inventory management has beenexecuted by displaying the information about the commodities (a kind ofcommodities and cost of commodities and so on)in a bar code as aninformation medium, reading the bar code with the bar code reader, andprocessing the information in a host computer.

Recently, also in a physical distribution field, such work as anassortment is often executed by displaying a bar code as an informationmedium on the commodity and the box, and reading the bar code with a barcode reader.

Some of the devices for reading information like the bar code reader areprovided with a device for scanning light. Generally, a method in whichthe light scanning is executed by revolving a polygon mirror and agalvano mirror mechanically has been adopted for the traditional devicefor scanning light.

Accordingly, the device for scanning light provided with mechanicallymovable parts has caused some problems that a controllability isdeteriorated and a response delay occurs and so on, and has caused somedeficiencies that the optical axis is slipped off by the mechanicalvibration and so on.

On the other hand, various methods have been suggested for a displaydevice which displays a stereoscopic picture up to the present. Oneexample is a binocular method represented by a spectacle method in whicha cubic effect is obtained by binocular convergence and binocularparallax, letting the left and right eyes look at the differentpictures. Besides, a lenticular method of multiple-lens method exists asan extension of the binocular method. A principle of the stereoscopicvision in the lenticular method is the same as the binocular method.

Only unnatural stereoscopic pictures can be seen in such method forstereoscopic display, since no difference (kinetic parallax) occurs inthe stereoscopic pictures even if the observer moves his head from leftto right.

Holographic stereogram is cited as a method to solve these problems. Inholographic stereogram, the natural cubic effect can be obtained even ifthe observer moves his head from left to right, since thetwo-dimensional pictures including the parallax are registered in asegment hologram of vertically slender slit form, and a large number ofthese pictures are arranged horizontally. Besides, holographicstereogram including vertical parallax also exists.

First of all, an object will be photographed moving the camera positionvertically if the holographic stereogram which has a vertical parallaxis given as an example.

Then, a laser light is applied to the film to which the object wasphotographed, an object light is beamed by projecting the film againstthe diffusion board with lens, a slit of a slit board is arranged infront of the hologram dry plate corresponding to the projectionposition, and the interference fringes are exposure-registered byinterfering with the reference light.

Further, a method for preparing an imaged hologram also exists. Namely,the imaged holographic diagram (image type holographic stereogram) isprepared by applying the laser light to the hologram which was preparedas mentioned above so that the light will be converged into the replaylight source indicated as a virtual image, installing another hologramdry board in a display position of the image according to the objectlight wave-front converted by the hologram and exposing the dry board inirradiation of the reference light.

The image type holographic stereogram is capable of displaying thestereoscopic image by applying the replay light to it, reviewing it fromthe visual region in the wave-front conversion.

It is desirable that the stereoscopic image exists near the holographsurface so as to reduce the fatigue of the observer's eyes, when thestereoscopic display is executed. In the above-mentioned holographicstereogram, it is necessary to image the picture photographed by camera,since the stereoscopic images are replayed so that they will be piled upon the hologram surface.

On the other hand, in the image type holographic stereogram, thehologram surface and the stereoscopic image can be piled up withoutconverting the pictures, since the two-dimensional pictures are on thehologram. Besides, there are some advantages that the image surface willbe on the hologram surface and the chromatic aberration will not occur,even if the wavelength of the light which refers to the holographchanges and so on. Accordingly, it can be said that the stereoscopicdisplay by the image type holographic stereogram is easier to see.

Besides, an Audio Optical Deflecting system (AOD) consisting oftellurium dioxide crystal is used as another device for stereoscopicdisplay, and a display device provided with a galvano mirror scanner,polygon mirror and a lens is also known. In the device, the interferencefringes formed on the hologram dry board are calculated by the computerfrom the three-dimensional data of the object which is displayed as ahologram. The data of the interference fringes are written into a framebuffer of the computer, and a picture signal and a synchronizationsignal are transmitted to the display unit.

In the display unit, the picture signal and the synchronization signalare separated into an optical scanning partial synchronization signaland a hologram signal which activates the audio optical deflectingsystem from the compound hologram signal for CRT display of thecomputer. At this moment, the hologram signal should be intermingledwith the 100 MHz carrier wave, since the frequency band necessary foractivating the audio optical deflecting system is from 50 MHz to 100MHz. The refractive index variation which is modulated resilientlyoccurs, when its transmission signal is converted into an ultrasonicwave by the ultrasonic transducer of the audio optical deflecting system(AOD) and the crystal within the audio optical deflecting system (AOD)istransmitted by the ultrasonic wave. The diffracted light can be obtainedif the laser light is injected into there. Although a hologram is formedwithin the audio optical deflecting system (AOD) by these actions, thehologram should be stopped by synchronizing the polygon mirror in soundspeed and revolving it, since the hologram is moving in sound speed(slow shear wave of the tellurium dioxide crystal, 617 per second). Atthis moment, the polygon mirror is also used for scanning the smallelement holograms horizontally at the same time. The horizontal linehologram formed like this should be scanned vertically by the galvanomirror scanner to replay the three-dimensional image. Accordingly, thethree-dimensional image can be seen floating in the space in front ofoutgoing radiation lens installed behind the polygon mirror.

By the way, the high control accuracy can not be desired and themechanical control delay can not be avoided, if the device forstereoscopic display owns such mechanically movable parts as the polygonmirror and the galvano mirror scanner. Besides, such problems as theslippage of the light axle due to the occurrence of noises by themechanical resonance might result in obtaining a stereoscopic picture ofpoor quality. Further, such maintenance as a mechanical adjustment cannot be easily executed.

For this reason, the electronic display of the hologram using, forinstance, the spatial light modulation element in which the liquidcrystal is used as a deflecting part was also considered. However,although the picture element pitch of the liquid crystal display must bearound 1 μm so as to obtain an enough deflection angle (around 30degrees) when the liquid crystal is used as the deflecting part, it wasimpossible to do so in reality. Besides, in traditional LCD (LiquidCrystal Display), the spatial frequency of only the integral numbertwofold of the picture element can be represented, but the deflection ofthe non-stage using the LCD was inexecutable.

By the way, generally, it is necessary to obtain a phase distribution ofthe light by the calculation of the computer from the three-dimensionalobject to be displayed, and it is necessary to calculate the phasedistribution from the two-dimensional picture in connection with theimage type holographic stereogram, in order to display the hologramelectronically by using the spatial light modulation element in whichthe liquid crystal is used.

The calculation of the phase distribution divides the hologram surfaceinto the microscopic hologram regions, calculates the phase distributionper inaccurate region from the position coordinates and the intensity ofall sample points of the object and executes the calculation inconnection with all of the microscopic hologram regions. For thisreason, the calculation volume is increased considerably also in theimage type holographic stereogram in which the phase calculation isexecuted for the two-dimensional pictures.

Besides, it is necessary to calculate a phase distribution and the loadof the computer calculation becomes heavy, whenever the contents of thetwo-dimensional pictures to be displayed are changed, so the improvementof these points has been desired.

Accordingly, it is desirable that the stereoscopic display can beexecuted for the image type holographic stereogram without calculatingthe phase distribution even if the two-dimensional pictures are changed.

SUMMARY OF THE INVENTION

The object of the present invention is to realize an apparatus fordeflecting light which does not have a mechanically movable part, and inwhich the deflection of the non-stage is executable and the control iseasily executed.

The object of the present invention is to realize a device for scanninglight which does not have a mechanically movable part, and in which thelight scanning can be executed continuously, the control is easilyexecuted and the miniaturization is executable.

The object of the present invention is to realize a device for readinginformation whose controllability is good and reliability is high.

The object of the present invention is to realize a device forstereoscopic display provided with a beam deflection means which doesnot have a mechanically movable part.

Another object of the present invention is to realize a device forstereoscopic display provided with an apparatus for deflecting lightwhich owns an enough deflecting angle without a minute processing of thepicture element, and in which the deflection of the non-stage isexecutable.

Another object of the present invention is to realize a device forstereoscopic display which executes a stereoscopic display withoutcalculating a phase distribution. The following means were adopted forthe present invention so as to attain at least one of theabove-mentioned objects.

An apparatus for deflecting light of the present invention comprises:(a) at least one pair of transference electrodes arranged facing oneanother; (b) a drive circuit which applies a voltage among thetransference electrodes; and (c) a liquid crystal which is insertedamong the transference electrodes, and whose parallel stripes whichfunction as a diffraction grating when the voltage is applied among thetransference electrodes are produced at a pitch corresponding to theapplied voltage.

In the apparatus for deflecting light of the present invention, theliquid crystal whose anisotropy of a permittivity is less than 0 isideal. Hereupon, the anisotropy of the permittivity means a value inwhich the permittivity of minor axis direction is subtracted from thepermittivity of the major axis direction in the liquid crystal. It isalso referred to as a permittivity difference.

Besides, it is understood that the pitch of the parallel stripes whichoccurs in the liquid crystal becomes narrower and the angle ofdiffraction gets bigger in proportion to the enlargement of the appliedvoltage. In the apparatus for deflecting light of the present invention,it is also possible to apply a voltage whose voltage value changestemporally among the transference electrodes by the drive circuit. Bythese actions, the angle of diffraction can be changed temporally, andit will be possible to control the angle of diffraction electrically.

Both dc voltage and alternating voltage can be used as the appliedvoltage.

A device for scanning light of the present invention comprises: (a) anapparatus for deflecting light whose liquid crystal is inserted amongthe transference electrodes arranged facing one another, and whoseparallel stripes which function as a diffraction grating when thevoltage is applied to the transference electrodes are produced at apitch corresponding to the applied voltage in the liquid crystal; (b) adrive circuit which applies a voltage whose voltage value changestemporally among the transference electrodes of the apparatus fordeflecting light; and (c) a light source which beams the light whichwill be injected into the apparatus for deflecting light.

The light can be scanned b)y using the diffracted light which is anoutgoing light of the apparatus for deflecting light as a scanninglight, since the angle of diffraction will change temporally if the sizeof the applied voltage of the apparatus for deflecting light is changedtemporally.

In the device for scanning light of the present invention, an opticalelement for converging light can be installed on the incident light sideor the outgoing light side of the apparatus for deflecting light. Theconvex lens can be exemplified as the optical element for converginglight.

The optical element for converging light can bring the image formationpoint of the light closer to the apparatus for deflecting light,compared with the case that the apparatus for deflecting light does nothave an optical element for converging light, when the light beamed fromthe light source is a focusing ray. The optical element for converginglight can converge the light beamed from the light source and make itform as a image, when the light beamed from the light source is adivergent ray or a parallel ray.

In the device for scanning light of the present invention, an incidentlight angle of the incident light against the apparatus for deflectinglight can be set almost equally to a Bragg angle of the diffracted lightused for the scanning light. By these actions, the diffractionefficiency can be maximized, and the intensity of the diffracted lightused as a scanning light can be bigger than the intensity of otherdiffracted light.

In the device for scanning light of the present invention, an opticalelement which enlarges a deflection angle of the scanning lightsubstantially can be installed on the outgoing light side of theapparatus for deflecting light. The scanning width of the scanning lightcan be enlarged and the device for scanning light can be miniaturized,if the deflection angle of the scanning light can be enlarged.

A convex lens, a concave lens, a convex mirror and a hologram and so oncan be exemplified as the optical element which enlarges the deflectionangle of the scanning light substantially.

In the device for scanning light of the present invention, an aperturecan be installed between the light source and the apparatus fordeflecting light, Besides, the beam diameter can be reduced and thewished-for beam shape can be set by the aperture.

Especially, the reflected light intensity contrast of the reflectedlight which reflects in the information medium can be improved, when thedevice for scanning light provided with the aperture is included in thedevice for reading information.

The device for scanning light of the present invention can be providedwith a variable mechanism which makes a clearance along an optical axisdirection from the light source to the optical element for converginglight variable. Namely, either the light source or the optical elementfor converging light is fixed so that the other side will be moved bythe variable mechanism along the optical axis direction. Either thelight source or the optical element for converging light can be moved bythe variable mechanism. By these actions, the position of the imageformation point of the scanning light can be made variable.

The device for scanning light of the present invention can be providedwith: (a) a half mirror which reflects an outgoing light of the opticalelement for converging light towards the direction alienated from theapparatus for deflecting light; (b) a second optical element forconverging light which converges the reflected light beamed from thehalf mirror; (c) a reflecting member which reflects the outgoing lightof the second optical element for converging light and lets thereflected light permeate through the second optical element forconverging light and the half mirror to inject it into the apparatus fordeflecting light; and (d) a variable mechanism which changes a clearancealong an optical axis direction from the second optical element forconverging light to the reflecting member.

In this case, either the second optical element for converging light orthe reflecting member is fixed so that the other side will be moved bythe variable mechanism along the optical axis direction. Either thesecond optical element for converging light or the reflecting member canbe moved by the variable mechanism.

In the device for scanning light of the present invention, a pluralityof apparatuses for deflecting light can be provided, the apparatuses fordeflecting light can be arranged in layers so that the parallel stripeswhich occurs in each apparatus for deflecting light will be crossed oneanother, and a voltage can be applied to each of the apparatuses fordeflecting light mutually by the drive circuit.

By these actions, the scanning light can be scanned to a plurality ofdirections changing the scanning directions in order. Hereupon, it isnot always necessary to make the apparatuses for deflecting lightcontact one another so as to pile up the apparatuses for deflectinglight, and a crevice can be existed among the apparatuses for deflectinglight. The crossed axes angle is not limited in particular.

In the device for scanning light of the present invention, a polarizercan be installed on the outgoing light side of the apparatus fordeflecting light. The polarizer shuts down almost all of the unnecessarydiffracted lights except the scanning light. As a result, the device forscanning light will be hardly influenced by any diffracted lights exceptthe scanning light, the performance of the device for scanning light canbe improved, and the simplification of the device and the extension ofthe degree-of-freedom of the design can be attained.

In the device for scanning light of the present invention, thepolarizers can be installed on the outgoing light side of the apparatusfor deflecting light, and the polarizers can be arranged so that thepolarizing direction of the polarizer will be almost perpendicularagainst the polarizing direction of the incident light to the apparatusfor deflecting light.

The laser light of the linearly polarized light of S polarization or Ppolarization is desirable as a light beamed from the light source. Thepolarizer can be arranged between the light source and the apparatus fordeflecting light so that only the linearly polarized light componentwill be injected into the apparatus for deflecting light, when the lightbeamed from the light source is not the linearly polarized light. Thedevice for scanning light of the present invention can be used for adevice for scanning light included in a bar code reader and a laserprinter and so on.

A device for reading information of the present invention comprises: (a)an apparatus for deflecting light whose liquid crystal is inserted amongthe transference electrodes arranged facing one another, and parallelstripes which function as a diffraction grating when the voltage isapplied to the transference electrodes are produced at a pitchcorresponding to the applied voltage; (b) a drive circuit which appliesa voltage whose voltage value changes temporally among the transferenceelectrodes of the apparatus for deflecting light; (c) a light sourcewhich beams the light which will be injected into the apparatus fordeflecting light; and (d) an apparatus for detecting light which detectsa reflected light when the scanning light diffracted by the apparatusfor deflecting light is reflected in an information medium.

The scanning light beamed from the device for scanning light isirradiated to the information medium, and is reflected in theinformation medium, then its reflected light is injected into the devicefor detecting light. The light signal inputted into the device fordetecting light is converted into an electric signal by appropriatemeans to be read.

In the device for reading information of the present invention, the barcode can be substituted for the information medium.

In the device for reading information of the present invention, shadingmeans for cutting off a zero-order diffracted light of the device fordeflecting light can be installed on the outgoing light side of theapparatus for deflecting light.

By these actions, the reflected light of the transmitted light can notbe injected into the device for detecting light, since the transmittedlight of the apparatus for deflecting light is cut off by the shadingmeans. Accordingly, the reading accuracy will be improved.

A device for stereoscopic display of the present invention comprises:(a) two-dimensional-picture-display means for displaying two-dimensionalpictures which vary in visual directions; and (b) beam deflection meansfor deflecting a light beamed from a picture element which organizes thepictures of the picture display means. The apparatus for deflectinglight whose liquid crystal is inserted among the transferenceelectrodes, and parallel stripes which function as a diffraction gratingwhen a voltage is applied among the transference electrodes are producedat a pitch corresponding to the applied voltage is used for the beamdeflection means.

In the device for stereoscopic display of the present invention, thephotographed pictures are inputted from a plurality of visualdirections. The inputted plural parallax pictures are displayed on thetwo-dimensional picture display means. Then, inputted pictures aredeflected to the corresponding designated visual regions respectively.For instance, the picture inputted from the first visual direction isdeflected to the virtual first aperture, the picture inputted from thesecond visual direction is deflected to the virtual second aperture andthe picture inputted from n the visual direction is deflected to thevirtual n the aperture. By these actions, the angle relation between theobject and the camera when the picture is inputted will be same as theangle relation between the observer and the displayed picture when thepicture is replayed, so the stereoscopic picture can be replayed.

Each of the parallax pictures in one time t=t1 should be rearranged intime series to display the two-dimensional pictures in order during Δt(for instance, Δt=1/30 seconds) when an animation is replayed (thepicture display of Scene 1). The parallax pictures in t=t1+Δt should bearranged in the time series similarly to execute the displays, afterexecuting the displays on the basis of the number of visual points (thepicture display of Scene 2). The animation should be displayed byrepeating these actions.

In the device for stereoscopic display of the present invention, adevice for stereoscopic picture display without mechanically movableparts can be realized, since the apparatus for deflecting light intowhich the liquid crystal is inserted is used as the beam deflectionmeans.

The device for stereoscopic display of the present invention comprises:(a) a line division unit for dividing a picture photographed by a camerainto a number of visual points; (b) a time series rearrangement unit forrearranging the two-dimensional pictures divided by the line divisionunit in the time series; (c) a two-dimensional picture display unit forreplaying and controlling the two-dimensional pictures rearranged by thetime series rearrangement unit in a time series order. The beamdeflection means can deflect the two-dimensional pictures displayed bythe two-dimensional picture display means to a virtual aperturecorresponding to an camera visual point of the plural cameras.

In the device for stereoscopic display of the present invention, thepictures can be deflected to a horizontal direction by the beamdeflection means.

In the device for stereoscopic display of the present invention, thepictures can be deflected to a vertical direction by the beam deflectionmeans.

The device for stereoscopic display of the present invention can beprovided with first beam deflection means for deflecting the pictures tothe horizontal direction and second beam deflection means for deflectingthe pictures to the vertical direction.

In the device for stereoscopic display of the present invention, thetwo-dimensional picture display means has a picture element fordisplaying the pictures, and the beam deflection means can be providedindependently per picture element which organizes the pictures.

In the device for stereoscopic display of the present invention, thetwo-dimensional picture display means has a picture element fordisplaying the pictures and the beam deflection means can be providedextending over a plurality of picture elements which organize thepictures.

In the device for stereoscopic display of the present invention, thebeam deflection means executes the deflection only to the horizontaldirection, and light diffusion means for diffusing the light to thevertical direction can be provided.

In the device for stereoscopic display of the present invention, thebeam deflection means is controlled by the deflection control unit andthe deflection control unit can refer to a phase-distribution table inwhich a phase-distribution data are stored to determine a deflectionangle of the beam deflection means. By these actions, it is notnecessary to calculate the phase distribution whenever the picture isswitched.

In the device for stereoscopic display of the present invention, a pairof polarizing plates which are arranged before and behind the beamdeflection means and whose deflecting directions are crossed in an angleof 90 degrees ±10 can be provided.

In the device for stereoscopic display of the present invention, anelimination time of the display screen can be prepared in the deflectioncontrol unit in which the beam deflection means is controlled beforerewriting the screen, when the deflection is moved from one virtualaperture to the next virtual aperture by the beam deflection means, andthe deflection can be stopped during the time.

In the device for stereoscopic display of the present invention, anelimination time of the display screen can be prepared in the deflectioncontrol unit in which the beam deflection means is controlled beforerewriting the screen, when the deflection is moved from one visualaperture to the next virtual aperture by the beam deflection means, andthe deflection can be stopped during the time and the intensity of theimage display by the two-dimensional picture display means can bedarkened at the same time.

The device for stereoscopic display of the present invention can beprovided with a record/replay unit for recording and replaying aphotographed picture.

A system for stereoscopic picture communication of the present inventioncomprises a transmission side that transmits a plurality oftwo-dimensional pictures which vary in visual directions through acommunication network and a receiving side that receives the transmittedtwo-dimensional pictures, and displays them by the two-dimensionalpicture display means which displays the received two-dimensionalpictures, and displays a stereoscopic picture in a remote location bydeflecting the light beamed from the picture element which organizes thepictures of the picture display means corresponding to the differentvisual directions in the beam deflection means. An apparatus fordeflecting light whose liquid crystal is inserted among the transferenceelectrodes arranged facing one another, and parallel stripes whichfunction as a diffraction grating when the voltage is applied among thetransference electrodes are produced at a pitch corresponding to theapplied voltage in the liquid crystal is used for the beam deflectionmeans.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chemical formula of a concrete example of a liquid crystalused for an apparatus for deflecting light of the present invention.

FIG. 2 is a basic construction diagram of an apparatus for deflectinglight according to the embodiment 1 of the present invention.

FIG. 3 and FIG. 4 are principle diagrams of an apparatus for deflectinglight according to the embodiment 1 of the present invention.

FIG. 5 is a construction diagram of a device for scanning lightaccording to the embodiment 2 of the present invention, and (A)indicates a case that the scanning light scans one side bordering thelight axes, (B) indicates a case that the scanning light scans bothsides extending over the light axes.

FIG. 6 is a diagram indicating an example of a waveform of a voltageapplied to an apparatus for deflecting light of the present invention,and (A) and (C) indicate a case of alternating voltage, (B) indicates acase of dc voltage.

FIG. 7 is a construction diagram of a device for scanning lightaccording to the embodiment 3 of the present invention.

FIG. 8 is a construction diagram of a device for scanning lightaccording to the embodiment 4 of the present invention, and (A)indicates a case that a convex lens is used as an optical element whichenlarges a deflection angle, (B) indicates a case that a concave lens isused as an optical element which enlarges a deflection angle.

FIG. 9 is a construction diagram of a relative example of a device forscanning light of the embodiment 4 of the present invention.

FIG. 10 is a construction diagram of a device for scanning lightaccording to the embodiment 5 of the present invention.

FIG. 11 is a construction diagram of a device for scanning lightaccording to the embodiment 6 of the present invention.

FIG. 12 is an visual strabismus diagram of a bar code reader as a devicefor reading information of the present invention.

FIG. 13 is a construction diagram of a device for reading informationaccording to the embodiment 7 of the present invention, and (A) is adiagram describing an optical path when the light is scanned, (B) is adiagram describing an optical path when the light is detected.

FIG. 14 is a construction diagram of a device for reading informationaccording to the embodiment 8 of the present invention.

FIG. 15 is a construction diagram of a device for reading informationaccording to the embodiment 9 of the present invention.

FIG. 16 is a construction diagram of a device for reading informationaccording to the embodiment 10 of the present invention.

FIG. 17 is a construction diagram of a device for reading informationaccording to the embodiment 11 of the present invention.

FIG. 18 is a construction diagram of a device for reading informationaccording to the embodiment 12 of the present invention.

FIG. 19 is a construction diagram of a device for reading informationaccording to the embodiment 13 of the present invention.

FIG. 20 is a construction diagram of a device for reading informationaccording to the embodiment 14 of the present invention.

FIG. 21 is a diagram indicating a method for arranging three apparatusesfor deflecting light in a device for reading information of theembodiment 14 of the present invention.

FIG. 22 is a diagram indicating a scanning state of a scanning light ina device for reading information of the embodiment 14 of the presentinvention.

FIG. 23 is a strabismus diagram indicating a visual shape of a devicefor reading information according to the embodiment 15 of the presentinvention.

FIG. 24 is a strabismus diagram of a device for reading information anda host computer according to the embodiment 16 of the present invention.

FIG. 25 is a strabismus diagram of a device for reading informationaccording to the embodiment 17 of the present invention.

FIG. 26 is a strabismus diagram of a device for reading informationaccording to the embodiment 18 of the present invention.

FIG. 27 is a block diagram indicating a construction of a device forstereoscopic display according to the embodiment 19 of the presentinvention.

FIG. 28 is a diagram indicating a state in which an original picturecaptured by a camera is divided into a visual point number of lines in adevice for stereoscopic display of the embodiment 19 of the presentinvention.

FIG. 29 is a diagram indicating a state in which a line picture isrearranged after the division in a device for stereoscopic display ofthe present invention.

FIG. 30 is a plane construction diagram of an apparatus for stereoscopicdisplay according to a device for stereoscopic display of the embodiment19 of the present invention.

FIG. 31 is a block diagram indicating a control system of a deflectingsystem in a device for stereoscopic display of the embodiment 19 of thepresent invention.

FIG. 32 is a diagram indicating a VGM apparatus for deflecting light ina device for stereoscopic display of the embodiment 19 of the presentinvention.

FIG. 33 is a diagram indicating a state in which a voltage is applied toa VGM apparatus for deflecting light in a device for stereoscopicdisplay of the embodiment 19 of the present invention.

FIG. 34 is a diagram indicating a state of a phase distribution(interference fringe) when a voltage is applied to a VGM apparatus fordeflecting light in a device for stereoscopic display of the embodiment19 of the present invention.

FIG. 35 is a graph diagram indicating a relation between an appliedvoltage and a spatial frequency of a liquid crystal used for a VGMapparatus for deflecting light in a device for stereoscopic display ofthe embodiment 19 of the present invention.

FIG. 36 is a construction diagram of an apparatus for stereoscopicdisplay which only has a horizontal parallax error in a device forstereoscopic display of the embodiment 19 of the present invention.

FIG. 37 is a diagram indicating a first method for deflection in anapparatus for deflecting light in a device for stereoscopic display ofthe embodiment 19 of the present invention.

FIG. 38 is an arrangement construction diagram of a polarizing plate ina device for stereoscopic display of the embodiment 19 of the presentinvention.

FIG. 39 is a diagram indicating a state of a transmitted light of anapparatus for deflecting light when no polarizing plate exists.

FIG. 40 is a diagram indicating a state of a zero-order light switchingby a polarizing plate.

FIG. 41 is a diagram indicating a method for deflecting light when anapparatus for deflecting light is a single picture element in a devicefor stereoscopic display of the embodiment 19 of the present invention.

FIG. 42 is a timing chart diagram when an elimination of screen isexecuted among picture displays in a device for stereoscopic display ofthe embodiment 19 of the present invention.

FIG. 43 is a diagram indicating an example of a second method fordeflecting light in an apparatus for deflecting light in a device forstereoscopic display of the embodiment 19 of the present invention.

FIG. 44 is a construction diagram when it has a horizontal parallax anda vertical parallax in a device for stereoscopic display of theembodiment 20 of the present invention.

FIG. 45 is a descriptive diagram indicating a calculation principle of aphase distribution aimed at the two-dimensional picture in a device forstereoscopic display of the embodiment 21 of the present invention.

FIG. 46 is a descriptive diagram indicating a deflection function of anapparatus for deflecting light when it has a horizontal parallax and avertical parallax in a device for stereoscopic display of the embodiment21 of the present invention.

FIG. 47 is a descriptive diagram of a method for calculating a phasedistribution which has a deflecting function of FIG. 46 in a device forstereoscopic display of the embodiment 21 of the present invention.

FIG. 48 is a descriptive diagram of a phase distribution storage tablewhen it has a horizontal parallax and a vertical parallax in a devicefor stereoscopic display of the embodiment 21 of the present invention.

FIG. 49 is a descriptive diagram of a two-dimensional picture storagetable when it has a horizontal parallax and a vertical parallax in adevice for stereoscopic display of the embodiment 21 of the presentinvention.

FIG. 50 is a descriptive diagram indicating a deflecting function of anapparatus for deflecting light when it has a horizontal parallax in adevice for stereoscopic display of the embodiment 21 of the presentinvention.

FIG. 51 is a descriptive diagram of a method for calculating a phasedistribution which realizes a deflecting function of FIG. 50 in a devicefor stereoscopic display of the embodiment 21 of the present invention.

FIG. 52 is a descriptive diagram of a phase distribution storage tablewhen it only has a horizontal parallax in a device for stereoscopicdisplay of the embodiment 21 of the present invention.

FIG. 53 is a descriptive diagram of a two-dimensional picture storagetable when it only has a horizontal parallax in a device forstereoscopic display of the embodiment 21 of the present invention.

FIG. 54 is a descriptive diagram indicating a deflecting function of anapparatus for deflecting light when the picture is divided in a devicefor stereoscopic display of the embodiment 21 of the present invention.

FIG. 55 is a descriptive diagram of a method for calculating a phasedistribution which realizes a deflecting function of FIG. 54 in a devicefor stereoscopic display of the embodiment 21 of the present invention.

FIG. 56 is a descriptive diagram of a phase distribution storage tablewhen the picture is divided in a device for stereoscopic display of theembodiment 21 of the present invention.

FIG. 57 is a descriptive diagram of a deflecting state when a lenticularlens is installed on FIG. 54 to be magnified in a vertical directionoptically in a device for stereoscopic display of the embodiment 21 ofthe present invention.

FIG. 58 is a schematic diagram of a stereoscopic display record/replaysystem in a device for stereoscopic display of the embodiment 22 of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred concrete examples of the present invention will bedescribed on the basis of the drawings as follows.

V. G. M Phenomenon

First of all, V. G. M phenomenon will be described.

It has been reported that the parallel stripes of the number μm pitchwill appear when the voltage exceeds some fixed threshold, if some kindof nematic liquid crystal molecules are caught in among the transferenceelectrodes to apply a dc voltage or an alternating voltage (B. H. Sofferet, al. Opt. Eng. 22, 6, 1983). The phenomenon is referred to as V. G. M(Variable Grating Mode).

The parallel stripes are caused by the distribution of the secondaryorientation within the liquid crystal, and the pitch (namely, thespatial frequency) of the parallel stripes changes depending on the sizeof the applied voltage.

Besides, the permittivity difference of the liquid crystal in which theV. G. M phenomenon occurs is often Δε<0. The representative example ofthe liquid crystal in which V. G. M phenomenon occurs is shown inFIG. 1. The liquid crystal is on the market as N-4 of Merc corporationand is available.

The angle of diffraction can be changed by changing the applied voltage,since the parallel stripes function as a diffraction grating. Besides,it is understood that the pitch of the parallel stripes becomes narrowerand the angle of diffraction gets bigger in proportion to theenlargement of the applied voltage.

The apparatus for deflecting light of the present invention makes use ofthe V. G. M phenomenon.

Apparatus for Deflecting Light

Then, the preferred embodiments of the apparatus for deflecting light ofthe present invention will be described referring to the drawings.

EMBODIMENT 1 Apparatus for Deflecting Light

FIG. 2 is a basic construction diagram of the apparatus for deflectinglight of the present invention. The apparatus for deflecting light 100comprises a pair of transparent glass plates 104, 104 provided with atransference electrode 102 and a orientation film 103 on one surfacearranged facing one another and a liquid crystal (for instance, theabove-mentioned N-4 made by Merck enterprise) 105 in which the V. G. Mphenomenon occurs and which is inserted between the glass plate 104 andthe glass plate 104. The drive circuit 106 is connected to thetransference electrodes 102, 102 so that an alternating voltage or a dcvoltage can be applied among the transference electrodes.

In the apparatus for deflecting light 100, the parallel stripes appearwhen the voltage is applied between the transference electrode 102 andthe transference electrode 102, and the parallel stripe functions as andiffraction grating. Accordingly, as shown in FIG. 3 and FIG. 4, and thetransmitted light (the zero-order light) and the ±primary and ±secondary diffracted light appear on the outgoing light side, when thelight beamed from the light source 211 is injected into the apparatusfor deflecting light 100. Besides, in the drawings, the high-orderdiffracted light more than the tertiary light is omitted since itsintensity is so small.

It has been reported that the polarization direction will beperpendicular in the odd-order diffracted light, the zero-order lightand the even-order diffracted light, if the incident light is convertedinto the linearly polarized light (B. H. Soffer et,al. Opt. Eng 22, 6,1983). Namely, the zero-order light and the even-order diffracted lightwill be S polarized light and the odd-order diffracted light will be Ppolarized light, if the incident light is S polarized light.

The light will be deflected if one of the diffracted lights is used as aoutgoing light. Generally, the diffracted light whose intensify is thestrongest of the diffracted lights is used as the outgoing light, and itis often + primary diffracted light. Further, as mentioned hereinafter,the zero-order light and the secondary light can be removed by using thepolarized as occasion demands.

The pitch of the parallel stripes will change and the angle ofdiffraction will change, if the size of the voltage applied between thetransference electrode 102, and the transference electrode 102 ischanged. Accordingly, the angle of diffraction can be fixed if the sizeof the voltage applied between the transference electrode 102 and thetransference electrode 102 is fixed, and the angle of diffraction willbe variable if the size of the voltage applied between the transferenceelectrode 102 and the transference electrode 102 is variable.Especially, the angle of diffraction can be changed continuously if thevoltage value is changed continuously.

Further, the apparatus for deflecting light can be produced in the sameway as the common liquid crystal. For instance, first of all, therubbing is executed by forming the transference electrode pattern 102 oneach back of one pair of transparent glass plate 104 and spreading theorientation film 103 over the back of the each transparent glass plate104. Then, the transparent glass plates 104, 104 are arranged facing oneanother by making the transference electrode 102 the inner side so as tovacuum-lock them by spreading and inserting a unillustrated sphericalspacer between them. Then, the producing of the apparatus for deflectinglight is completed by breaking a vacuum and filling up the transparentglass plates 104, 104 with the liquid crystal.

The transference electrodes patterns 102, 102 do not have to be the sameas the liquid crystal display and the transference electrodes 102, 102only have to be connected to the surface of the inner side of thetransparent glass plate 104 wholly.

Device for Scanning Light

Then, the preferred embodiments of a device for scanning light of thepresent invention will be described referring to the drawings. Thedevice for scanning light of the present invention makes use of theapparatus for deflecting light.

EMBODIMENT 2 Device for Scanning Light

FIGS. 5(A), (B) are the construction diagrams indicating the embodimentsof the device for scanning light 200 of the present inventionrespectively.

The device for scanning light comprises an apparatus for deflectinglight 100, a light source 211 arranged on the incident light side of theapparatus for deflecting light 100, a condensing lens (the opticalelement for converging light) 212 consisting of the convex lens arrangedbetween the apparatus for deflecting light 100 and the light source 211and a drive circuit 213 which applies a voltage to the apparatus fordeflecting light 100. The drive circuit 213 is capable of applying thevoltage whose size changes periodically to the apparatus for deflectinglight 100.

The light source 211 and the apparatus for deflecting light 100 arearranged on the optical axis of the condensing lens 212. The laser lightof S polarized light is beamed from the light source 211, and isconverted into the focusing light by the condensing lens 212. Theapparatus for deflecting light 100 is arranged closer to the condensinglens 212 than the image formation point by the condensing lens 212.Accordingly, the light which permeated through the condensing lens 212is deflected by the apparatus for deflecting light 100 before beingconverged into the image formation point.

FIG. 6 is a diagram indicating an example of a waveform of a voltageapplied between the transference electrode 102 and the transferenceelectrode 102 of the apparatus for deflecting light 100. FIGS. 6(A), (C)indicate a case of alternating voltage, FIG. 6(B) indicates a case of dcvoltage.

Although the alternating signal is given by the pulse in FIGS. 6(A),(C), the alternating signal is not limited to this alternating signal,and, for instance, the alternating signal whose voltage value increasesand decreases continuously can be substituted.

As mentioned hereinbefore, the angle of diffraction of the apparatus fordeflecting light 100 will change temporally, if the size of the voltageapplied between the transference electrode 102 and the transferenceelectrode 102 is changed temporally. Accordingly, the scanning lightwhich is a diffracted light will be scanned rectilinearly if the lightis injected into the apparatus for deflecting light 100. Further, thescanning cycle of the scanning light will be synchronized with the cycleof the voltage.

Hereupon, the scanning light should be scanned on one side bordering theoptical axis of the condensing lens 212 as shown in FIG. 5(A), when thevoltage changes either in a positive region or in a negative region likeFIGS. 6(A), (B). The scanning light should be scanned on the both sidesextending over the light axes as shown in FIG. 5(B), when the voltagechanges both in the positive region and in the negative region like FIG.6(C). Further, the scanning speed of the scanning light will bedetermined by the frequency of the voltage applied to the apparatus fordeflecting light 100.

Hereupon, for instance, if the light beamed from the light source 211 isa semiconductor laser light of wavelength 670 nm, the waveform of thevoltage applied between the transference electrode 102 and thetransference electrode 102 is like FIG. 6(C) and the spatial frequencyof the parallel stripes which occur in the apparatus for deflectinglight 100 has changed within the limit from 0 to 1000/mm, the maximumvalue of the deflection angle will be ±21 degrees and the maximum valuewill be 42 degrees as a scanning angle θ shown in FIG. 5(B).

In FIG. 5(B), if the distance from the light source 211 to thecondensing lens 212 is 11.1 mm, and the focal length of the condensinglens 212 is 10 mm, the light which permeated through the condensing lens212 will be converged into a point where the distance b from thecondensing lens 212 is 100 mm to be formed as an image. Then, if thedistance c from the condensing lens 211 to the apparatus for deflectinglight 100 is 9 mm, the scanning width L of the scanning light will be 70mm.

According to the device for scanning light 200, the vibration will notoccur and the reply delay will not occur, since it does not have amechanically movable part. Besides, the optical axis will not be slippedoff, since the vibration does not occur.

In the case of the device for scanning light 200, the scanning width andthe scanning speed of the scanning light can be controlled electrically,so the controllability is very excellent. Especially, the scanning lightcan be scanned continuously by changing the voltage value applied to thetransference electrodes 102 continuously.

Besides, the image formation point of the light can be closer to theapparatus for deflecting light 100 compared with the case that thecondensing lens is not installed, and the device can be miniaturized,when the light beamed from the light source 211 is a focusing beam, ifthe condensing lens 212 as an optical element for converging light isinstalled on the incident light side of the apparatus for deflectinglight 100 like the embodiment 2. The light beamed from the light source211 can be converged to be formed as an image, if the light beamed fromthe light source 211 is a divergent beam or a parallel beam.

EMBODIMENT 3 Device for Scanning Light

FIG. 7 is a construction diagram indicating another embodiment of adevice for scanning light 200 of the present invention.

The device for scanning light 200 of the embodiment 3 is the same as theabove-mentioned device for scanning light 200 of the embodiment 2 byreason that it comprises an apparatus for deflecting light 100, a lightsource 211, a condensing lens 212 and a drive circuit 213.

The difference between the device for scanning light 200 of theembodiment 3 and the device for scanning light 200 of the embodiment 2is the fact that Bragg condition will be met when the parallel stripesof the apparatus for deflecting light of the embodiment 3 become thepredetermined spatial frequency, namely, the incident angle of the lightinjected into the apparatus for deflecting light 100 will be equal tothe angle of diffraction of the diffracted light used as a scanninglight.

The diffraction efficiency will be maximized and the intensity of thediffracted light used as a scanning light will be maximized, so theintensity of other diffracted light can be kept small sufficiently, whenBradd condition is met.

In the embodiment 3, for instance, if the light beamed from the lightsource 211 is a semiconductor laser light of the wavelength 670 nm, thewaveform of the voltage applied between the transference electrode 102and the transference electrode 102 is like FIG. 6(A) or (B), the spatialfrequency of the parallel stripes that occur in the apparatus fordeflecting light 1 has changed within the limit from 0 to 1000/mm andBradd condition is met by the spatial frequency of 1000/mm, the incidentlight angle α will be 19.6 degrees, and the scanning angle θ will be39.2 degrees.

If the distance from the light source 211 to the condensing lens 212 is11.1 mm, and the focal length of the condensing lens 212 is 10 mm, thelight which has permeated through the condensing lens 212 will beconverged into a point where the distance b from the condensing lens 212is 100 mm to be formed as an image. In this case, the scanning width Lof the scanning light can be 70 mm like the embodiment 2 if the distanceC from the condensing lens 211 to the apparatus for deflecting light 100is 2 mm.

EMBODIMENT 4 Device for Scanning Light

FIGS. 8(A), (B) are the construction diagrams indicating anotherembodiment of a device for scanning light of the present invention.

The device for scanning light 200 of the embodiment 4 is installed onthe outgoing light side of the apparatus for deflecting light 100 and isprovided with a convex lens 214 or a concave lens 215 closer to thecondensing lens 212 than the image formation point by the condensinglens 212, in addition to the components of the device for scanning light200 of the above-mentioned embodiment 3. The convex lens 214 or theconcave lens 215 functions to enlarge the deflection anglesubstantially.

First of all, the case that the convex lens and the concave lens do notexist will be considered as a comparison example. In this case, forinstance, if the light beamed from the light source 211 is asemiconductor laser light of the wavelength 670 mm, the waveform of thevoltage applied between the transference electrode 102 and thetransference electrode 102 is like FIG. 6(C), the spatial frequency ofthe parallel stripes which occurs in the apparatus for deflecting light100 has changed within the limit from 0 to 500/mm, the Bradd conditionis met by the spatial frequency of 400/mm, the incident light angle αwill be 7.7 degrees and the scanning angle θ will be 15.4 degrees.

In this case, the distance S from the apparatus for deflecting light 100to the image formation point must be 259 mm so that the scanning width Lof the scanning light will be 70 mm like the embodiment 2.

Hereupon, as shown in FIG. 8(A), the light deflected by the apparatusfor deflecting light 100 will be crossed with the optical axis in aposition which is about 7.5 mm to the outgoing light side from theconvex lens 214 after being injected into the convex lens 214, and itwill be widened again to be formed as a image, if the convex lens 214 ofthe focal distance 5 mm is installed on the optical axis which is commonto the condensing lens 214 in a position which is 15 mm to the outgoinglight side from the apparatus for deflecting light 100. The scanningwidth L of the scanning light will be 70 mm in a position which is about138.5 mm from the convex lens 214, since the displacement width of thelight in the convex lens 214 is about 4 mm.

Accordingly, the distance S from the apparatus for deflecting light 100to the image formation point will be about 153.3 mm, and it can beshortened only 105.5 mm compared with the distance S of 259 mm when theconvex lens is not installed.

As shown in FIG. 8(B), the light deflected by the apparatus fordeflecting light 100 will be diverged as though the focus existed in aposition which is 75 mm to the incident light side of the concave lens215 and will be formed as a image, if the concave lens 215 whose focaldistance is 50 mm is installed on the optical axis which is common tothe condensing lens 212 in a position which is 150 mm to the outgoinglight side from the apparatus for deflecting light 100. The scanningwidth L of the scanning light will be 70 mm in a position which is about56 mm from the concave lens 215, since the displacement width of thelight in the concave lens 215 is about 40 mm.

Accordingly, the distance S from the apparatus for deflecting light 100to the image formation part of the scanning light will be 206 mm, and itcan be shortened only 53 mm compared with the distance S of 259 mm whenthe concave lens is not installed.

EMBODIMENT 5 Device for Scanning Light

FIG. 10 is a construction diagram indicating another embodiment of adevice for scanning light of the present invention.

In the device for scanning light of the embodiment 5, a polarizer 216 isinstalled on the outgoing light side of the apparatus for deflectinglight 100, in addition to the components of the device for scanninglight of the above-mentioned embodiment 2. The functions of thepolarizer 216 will be described as follows.

As mentioned hereinbefore, the diffracted lights other than thediffracted light used as a scanning light also exist on the outgoinglight side of the apparatus for deflecting light 100. It sometimeshappens that a restriction will be added to the construction of thedevice for scanning light and the efficiency will receive a badinfluence, if such diffracted light exists.

For instance, the reading accuracy will be deteriorated, since thelights except the + primary light which is a scanning light will beirradiated to the bar code and its reflected light will be injected intothe apparatus for detecting light, if no difference exists in an angleof diffraction of each diffracted light, when the diffracted light isused for the bar code reader. On the other hand, it will be necessary todesign a hologram so that an angle difference will occur in an angle ofdiffraction of each diffracted light, if an attempt to improve thereading accuracy is made.

On the other hand, the extra diffracted lights except the scanning lightcan be cut off, if the polarizer 216 is installed on the outgoing lightside of the device for scanning light 100 of the present invention.

Hereupon, as shown in FIG. 10, it is assumed that the laser light of Spolarization is beamed from the light source 211, and the polarizer 216is arranged so that the polarization direction of the injected light andthe polarization direction of the polarizer 216 will be perpendicular.

Then, in the device for scanning light 200, the zero-order light (thetransmitted light) in which the polarizer 216 and the polarizationdirection are perpendicular the even-order diffracted light will be cutoff by the polarizer 216, and only + primary diffracted light and -primary diffracted light will permeate through the polarizer 216. Theexistence of the primary diffracted light will hardly be at issuepractically, since the angle difference between the +primary diffractedlight and the -diffracted light is large, even though the - primarydiffracted light is unnecessary when the - primary diffracted light isused as a scanning light.

Accordingly, the device for scanning light will hardly be influenced bythe diffracted lights except a scanning light, the efficiency of thedevice for scanning light can be improved, and the simplification of thedevice and the enlargement of degree of freedom of the design can beattained.

EMBODIMENT 6 Device for Scanning Light

FIG. 11 is a construction diagram indicating another embodiment of adevice for scanning light 200 of the present invention.

In the device for scanning light 200 of the embodiment 6, a polarizer216 is installed on the outgoing light side of the apparatus fordeflecting light 100, in addition to the components of the device forscanning light 200 of the above-mentioned embodiment 3.

In the embodiment 6, the device for scanning light is set up so that theincident light angle θ of the incident light against the apparatus fordeflecting light will be the Bragg angle of the + primary diffractedlight, when the parallel stripes of the apparatus for deflecting lingbecomes the predetermined spatial frequency (for instance, the maximumspatial frequency).

The diffraction efficiency of the + primary diffracted light will bemaximized and the intensity of the diffracted lights except the +primary diffracted light can be minimized sufficiently, if the incidentlight angle θ is set up as mentioned hereinbefore. Accordingly, theintensity of the - primary diffracted light which is capable ofpermeating through the polarizer 216 can be minimized to the utmost, andthe efficiency can be further improved than the case of theabove-mentioned embodiment 5.

Device for Reading Information

Then, the preferred embodiments of a device for reading information ofthe present invention will be described referring to the drawings. Thedevice for reading information of the present invention makes use of thedevice for scanning light.

What is called a bar code reader is one example of the device forreading information. The device for reading information will bedescribed taking the bar code reader for instance as follows.

The bar code reader of the present invention scans the light beam on thebar code by deflecting the light beamed from the light source in theapparatus for deflecting light, and controlling the voltage applied tothe apparatus for deflecting light in the drive circuit.

As shown in FIG. 12, there are three types of bar code reader 300. FIG.12(A) is a pen-type bar code reader 300. In this type, the light doesnot scan for itself and the operator scans the light by letting the barcode reader slip, bringing the point of the bar code reader into contactwith the bar code and reads the information.

FIG. 12(B) is a touch-type bar code reader 300. In this type, thescanning light scans for itself to read the information, even if theoperator does not operate the bar code reader 300. Namely, the scanninglight will scan for itself on the bar code if the operator puts thepoint 302 of the frame 301 of the bar code reader 300 on the bar code sothat it will be almost contacted.

FIG. 12(C) is a gun-type bar code reader 300. In this type, the bar codereader 300 is operated separating from the bar code. The gun-type barcode reader 300 is suitable for being used in a place where a gettingthe bar code reader 300 closer to the bar code is difficult. Thegun-type bar code reader 300 consists of two types of bar code reader300. Namely, the bar code reader 300 in which the light scans for itselfas mentioned hereinbefore and the bar code reader 300 in which the lightdoes not scan for itself.

Although the device for reading information of the present invention canbe applied to the type in which the scanning light does not scan foritself, the device becomes effective in particular when it is applied tothe type in which the scanning light scans for itself. The state of thebar code reader 300 of the type in which the scanning light scans foritself will be described in the following embodiment.

EMBODIMENT 7 Device for Reading Information

FIGS. 13(A), (B) are construction diagrams of optical systems of a barcode reader 300 of the present invention. The optical systems areincluded in the frame 301 of the bar code reader 300.

The bar code reader 300 comprises a device for scanning light 200, ahalf mirror 321 arranged between the light source 211 of the device forscanning light 200 and the condensing lens 212, and an apparatus fordetecting light 322.

As shown in FIG. 13(A), the light beamed from the light source 211 isinjected into the condensing lens 212 through the half mirror 321, andis deflected by the apparatus for deflecting light 100. Hereupon, thelight beam is scanned on the bar code 400 (the information medium),since the space of the fringes of the apparatus for deflecting light ischanged continuously by the drive signal transmitted from the drivecircuit 213.

As shown in FIG. 13(B), a part of the lights which reflected in bar code400 passes through the apparatus for deflecting light 100 movingbackward, passes through the condensing lens 212 and reflects in thehalf mirror 321 to be injected into the apparatus for detecting light322.

The reflected light can be formed as an image in the apparatus fordetecting light 322, if the distance from the light source 211 to thehalf mirror 321 is equal to the distance from the half mirror 321 to theapparatus for detecting light 322.

EMBODIMENT 8 Device for Reading Information

FIG. 14 is a construction diagram of an optical system in anotherembodiment of the bar code reader 300.

The bar code reader of the embodiment 8 is not provided with a halfmirror 321, but it is provided with a condensing lens 323 having thelight axes which crosses on the image formation point of the scanninglight against the light axes of the condensing lens 212, and theapparatus for detecting light 322 is installed in the rear (the outgoinglight side) of the condensing lens 323.

The light beam outputted from the device for scanning light 200 reflectsand scatters in the bar code 400. Accordingly, a part of the scatteredlights can be condensed by the condensing lens 323 to be formed as animage on the apparatus for detecting light 322, even if the optical axesof the condensing lens 212 and the condensing lens 322 are slipped off.

EMBODIMENT 9 Device for Reading Information

FIG. 15 is a construction diagram of an optical system in anotherembodiment of the bar code reader 300.

The difference between the bar code reader 300 of the embodiment 8 andthe bar code reader 300 of embodiment 9 is the fact that an aperture 329which has a hole is installed between the light source 211 of the devicefor scanning light 200 and the condensing lens 212 in the bar codereader 300 of the embodiment 9, even though the basic construction ofthe bar code reader 300 of the embodiment 9 is the same as the basicconstruction of the bar code reader 300 of the above-mentionedembodiment 8.

The beam diameter can be reduced and the predetermined reflected lightintensity contrast which is capable of discriminating the bar code 400can be adopted, if the aperture 329 is installed.

Further, the shape of the beams irradiated to the bar code 400 is notlimited to a circle and the beams of such various shapes as anelliptical can be irradiated to the bar code 400. The beam shape can beset up appropriately depending on the shape of the hole made on theaperture 329, if the aperture 329 is installed.

EMBODIMENT 10 Device for Reading Information

FIG. 16 is a construction diagram of an optical system of anotherembodiment of the bar code reader 300.

The bar code reader 300 comprises a device for scanning light 200corresponding to FIG. 7, an apparatus for detecting light 322 whichdetects the light that reflected in the bar code 400 and a condensinglens 323 installed on the incident light side of the apparatus fordetecting light 322.

The bar code reader 300 scans the light beam after it is confirmed thatthe light beam is irradiated to the bar code 400, since the detectionresult of the apparatus for detecting light 322 for reading bar codeswhen the scanning light is irradiated to the bar code 400 is differentfrom the detection result of the apparatus for detecting light when thescanning light is irradiated to the bar codes except the bar code 400.

For this reason, in the bar code reader 300, the size of the voltageapplied to the apparatus for deflecting light should be set to 0, andthe state that the light beam is not scanned at the start should becreated before the light is scanned. The light permeates through theapparatus for deflecting light without being deflected when the size ofthe voltage applied to the apparatus for deflecting light is 0.

It is judged that the light beam is irradiated to the bar code, when thereflected light of the transmitted light in the bar code 400 is detectedby the apparatus for detecting light 322 and the intensity of thereflected light reaches the predetermined level.

Then, a trigger occurs in the reflected light detection circuit 324 whenthe reflected light of the predetermined intensity is detected by theapparatus for detecting light, and the drive circuit 213 which appliesthe voltage to the apparatus for deflecting light 1 is switched ON bythe trigger signal so that the scanning light will be scanned.

It is judged that the light beam is not irradiated to the bar code, andthe scanning of the light beam is not executed after that, when theintensity of the reflected light does not reach the predetermined level.

Besides, the drive circuit can be switched ON manually after theoperator confirms visually that the transmitted light is positioned onthe-bar code 400.

EMBODIMENT 11 Device for Reading Information

FIG. 17 is a construction diagram of an optical system of anotherembodiment of the bar code reader 300.

The bar code reader 300 comprises a device for scanning light 200corresponding to FIG. 7, an apparatus for detecting light 323 whichdetects the light that reflected in the bar code 400, a condensing light323 installed on the incident light side of the apparatus for detectinglight and a shading plate(shading means) 326.

As mentioned hereinbefore, a transmitted light (zero-order light)appears with a diffracted light used as a scanning light on the outgoinglight side of the apparatus for deflecting light 100. It will sometimeshappen that the reading of the information become incorrect undercertain circumstances, if the zero-order light reflects in the bar code400 or the objects other than the bar code 400, and the reflected lightis injected into the apparatus for detecting light 322.

Accordingly, in the bar code reader 300, the shading plate 326 isarranged on the optical path of the transmitted light so that thetransmitted light will not come through to the outside of the bar codereader 300, in order to get rid of the influence of the noise upon theapparatus for detecting light 322. Further, the shading plate 326 can bemade up of, for instance, the frosted black non-scatterers.

EMBODIMENT 12 Device for Reading Information

Generally, in a bar code reader, the information can not be readcorrectly due to the shortage of the intensity of the reflected light,and the oversize of the diameter of the light beam for the width of thebar code, if the bar code to be read is not within the predeterminedrange before and behind the image formation point of the scanning light.And the range in which the bar code can be read is very limited.

However, the range in which the bar code is read can be widened toimprove the facility, if the image formation point of the scanning lightcan be made variable. In the embodiment 12, the image formation point ofthe scanning light is made variable, and its construction and the actionwill be described as follows.

FIG. 18 is a construction diagram of an optical system of a bar codereader 300 of the embodiment 12.

As shown in the image formation formula of the convex lens, the distancefrom the condensing lens 212 to the image formation point variesdepending on the distance from the condensing lens 212 to the lightsource 211, when the light of the light source 211 is formed as an imageby the condensing lens 212. Accordingly, the distance from the apparatusfor deflecting light 100 to the image formation point can be changed, ifthe distance from the light source 211 to the condensing lens 212 (thedistance along the optical axis of the condensing lens 212) can bechanged.

The bar code reader 300 of the embodiment 12 in which the light source211 is moved directly comprises a device for scanning light 211corresponding to FIG. 7, an apparatus for detecting light 322 whichdetects the light that reflected in the bar code 400, a condensing lensinstalled on the incident light side of the apparatus for detectinglight 322 and a moving device (variable mechanism) 327 which moves thelight source 211 back and forth following the optical axis direction ofthe condensing lens 212.

The moving device 327 can be made up of what is called piezo elementsusing the reverse voltage effect and a mechanical moving device can beused in place of the moving device 327.

Further, for instance, moving the position of the image formation pointaccordingly after judging whether or not the reading could be executednormally as a result of demodulating the signal of the reflected lightobtained by the apparatus for detecting light 322, or moving theposition of the image formation point by such instructions as operator'skey operation can be considered as the timing when the position of theimage formation point of the scanning light is moved back and forth.

EMBODIMENT 13 Device for Reading Information

Also in the bar code reader 300 shown in FIG. 19, the distance from theapparatus for deflecting light 100 to the image formation point is madevariable, the range in which the bar code can be read is widened and thefacility is improved.

The bar code reader 300 comprises a device for scanning light 200, anapparatus for detecting light 322 which detects the light that reflectedin the bar code and a condensing lens installed on the incident lightside of the apparatus for detecting light 322.

The device for scanning light comprises an apparatus for deflectinglight 100, a light source 211, a first condensing lens (an opticalelement for converging light) 212 consisting of the convex lens, a drivecircuit 213, a half mirror 217, a second condensing lens (a secondoptical element for converging light) 218 consisting of the convex lensand a reflected mirror 219.

The reflected mirror 219 is installed on the variable mechanism 330 andcan be moved by the variable mechanism 330 back and forth following theoptical axis of the second condensing lens 218.

The variable mechanism 330 comprises a reciprocation group 331 and adisplacement mechanism 332. The reciprocation group 331 is supported sothat it will be rotatable centering around its edge, and the reflectedmirror 219 is fixed on the other edge of the reciprocation group 331.

The reciprocation group 331 is reciprocated by the displacementmechanism 332 which was connected on its way. The displacement mechanismcan be made up of the piezo elements, and a mechanical moving device canbe used in place of the displacement mechanism.

The light beamed from the light source 211 passes through the firstcondensing lens 212 to be reflected in the half mirror 217, itsreflected light passes through the second condensing lens 218 to beformed as an image in the reflected mirror 219, the reflected lightwhich reflected in the reflected mirror 219 goes backward to passthrough the second condensing lens 218 for the second time, thereflected light permeates through the half mirror and is deflected inthe apparatus for deflecting light 100 to be converted into the scanninglight and the scanning light scans on the bar code.

In the bar code reader 300, the reflected mirror is moved back and forthalmost following the optical axis when the reciprocation group 331reciprocates, the distance from the apparatus for deflecting light tothe image formation point is changed by changing the distance from thesecond condensing lens 218 to the reflected mirror 219.

Besides, it is favorable that the displacement volume of the reflectedmirror can be enlarged by the principle of "lever", when thereciprocation group 331 is installed as mentioned hereinbefore, eventhough the reflected mirror can be moved back and forth directly by thedisplacement mechanism 332 without installing the reciprocation group331.

Further, various cases can be considered about the timing when theposition of the image formation point of the scanning light is movedback and forth, like the cases of the above-mentioned embodiment 12.

EMBODIMENT 14 Device for Reading Information

FIG. 20 is a construction diagram of an optical system in anotherembodiment of the bar code reader 300.

The bar code reader 300 comprises a device for scanning light 200, anapparatus for detecting light 322 which detects the light that reflectedin the bar code 400 and a condensing lens 323 installed on the incidentlight side of the apparatus for detecting light 323.

The device for scanning light 200 comprises three apparatuses fordeflecting light 100A, 100B, 100C, a light source 211, a condensing lens212 consisting of the convex lens and a voltage control unit (a drivecircuit) 213.

As shown in FIG. 21, the three apparatuses for deflecting light100A-100C are arranged in layers so that the directions of diffractionfringes (indicated by parallel lines of full lines in FIG. 21) whichoccur when the voltage is applied will be slipped off per 120 degreesone another.

As shown in FIGS. 20(A), (B), (C), in the three apparatuses fordeflecting light 100A-100C, the voltage controlled by the voltagecontrol unit 213 is applied without duplicating in order through theswitching circuit.

Accordingly, the light is not deflected in the other two apparatuses fordeflecting light and it merely permeates through the apparatuses fordeflecting light, even though the light is deflected in one apparatusfor deflecting light when the voltage is applied to one of theapparatuses for deflecting light.

As a result, in the bar code reader 300, the scanning light is scannedas indicated by the one-point chain line A of FIG. 21 and FIG. 22, whenthe voltage is applied to the apparatus for deflecting light 100A, thescanning line is scanned as indicated by the one-point chain line B whenthe voltage is applied to the apparatus for deflecting light 100B, andthe scanning light is scanned as indicated by the one-point line C whenthe voltage is applied to the apparatus for deflecting light 100C.

Namely, according to the bar code 300, the scanning light can be scannedin three directions slipped off per 120 degrees, the polarity for thebar code of the bar code reader 300 which is capable of reading the barcode is widened and the facility is improved.

EMBODIMENT 15 Device for Reading Information

The frame 301 of the bar code reader 300 can be transformed into suchtubular frames as a cylindrical frame, an elliptic tubular frame andrectangular tubular frame, since the optical system can be arrangedalmost on the one straight line in the device for reading information ofthe present invention.

FIG. 23 is a bar code reader 300 whose frame 301 is formed into acylindrical frame, FIG. 23(A) is a bar code reader 300 in which a notchunit 303 for marking is installed on the way of the frame 301, and FIG.23(B) is a bar code reader 300 in which a concave unit 304 whose shapeis easily gripped is installed on the point unit of the frame 301. Theoperator can easily decide the scanning direction of the scanning lightand the facility will be improved, if the frame 301 is formed asmentioned hereinbefore.

Besides, as shown in FIG. 23(C), the bar code reader 300 will be easilyoperated, the reading rate of the information will be improved and thefacility will be improved, if the point unit 302 of the frame 301 whichis the outgoing light side of the scanning light is widened into aspatular shape and clears the spatular shaped point unit 302 so that thescanning light will be formed as an image at the point of the point unit302 and the scanning light will be scanned in the longitudinal directionof the spatular shaped point unit 302.

EMBODIMENT 16 Device for Reading Information

In POS system, the information of the bar code should be decoded by adecoder and should be converted into the signal which can becomputerized, and should be transmitted to the computer, after readingthe information of the bar code.

The bar code reader 300 shown in FIG. 24(A) includes a decoder 311 withthe optical system 310 consisting of the device for scanning light 200and so on within the frame 301.

The bar code reader 300 shown in FIG. 24(B) includes the bar code reader311 within the computer 500. In this case, the bar code reader 300 onlyhas to include the optical system 301, so the bar code reader 300 can beminiaturized.

Further, the method for transmitting/receiving data between the bar codereader 300 and the computer 500 should be either radio transmission orwire transmission.

EMBODIMENT 17 Device for Reading Information

The bar code reader 300 can be provided with a function that switchesthe scanning light ON-OFF automatically or manually.

In this case, ON-OFF of the scanning light can be executed by switchingthe light source 211 ON-OFF, or a shutter installed on the optical pathcan be operated to interrupt or pass the light keeping the light source211 ON.

In FIG. 25, a switch 305 is installed on the frame 301 so that thetrigger will be generated by the switch 305 and the scanning light willbe synchronized with the trigger signal to execute ON-OFF of thescanning light.

ON-OFF operation of the scanning light also can be executedautomatically, even though it can be executed manually.

For instance, the switch 305 should be composed of touch sensors so thatthe switch 305 will be to ON when the operator touches the bar codereader 300, in order to execute ON operation of the scanning lightautomatically.

For instance, the trigger should be generated when the signal is notinputted into the decoder during the predetermined time so that thescanning light will be synchronized with the trigger signal to executeOFF operation of the scanning light, in order to execute OFF operationof the scanning light automatically.

EMBODIMENT 18 Device for Reading Information

The bar code reader 300 can be provided with notification means fornotifying the operator the state of the operation (for instance,"INFORMATION OF BAR CODE IS BEING READ", "READING IS COMPLETED","READING IS NO GOOD", "REOPERATION IS NEEDED" and so on).

The concrete example of the notification means installed on the bar codereader 300 is shown in FIG. 26.

In FIG. 26(A), the frame 301 is provided with an indicating lamp 306consisting of LED as notification means and so on. In FIG. 26(B), abuzzer 307 as notification means is included within the frame 301. InFIG. 26(C), a liquid crystal display 308 as notification means isinstalled on the frame 301.

Further, the notification means also can be installed on the computer500 side instead of being installed on the bar code reader 300.

Device for Stereoscopic Display

Then, the preferred embodiments of a device for stereoscopic display ofthe present invention will be described referring to the drawings. Thedevice for stereoscopic display of the present invention makes use ofthe apparatus for deflecting light constructed like the above-mentionedconstruction as beam deflection means for deflecting light.

EMBODIMENT 19 Device for Stereoscopic Display The Construction of theEmbodiment 19

A system for recording and replaying stereoscopic picture in theembodiment 19 will be described by referring to FIG. 27.

The system for recording and replaying stereoscopic picture comprises aplurality of cameras 1 (O1-On) which photographs an object 10 as atwo-dimensional picture, a line division unit 2 which divides thepicture photographed by the camera 1 into the number of visual points, atime series rearrangement unit 4 which rearranges the two-dimensionalpicture divided by the line division unit 2 in the time series, atwo-dimensional picture display control unit 5 which replays andcontrols the two-dimensional pictures rearranged by the time seriesrearrangement unit 4 in a time series order, an apparatus for display 6which replays the two-dimensional pictures controlled by thetwo-dimensional picture display control unit 5 in the time series order,a deflection control unit 7 which deflects and controls thetwo-dimensional pictures displayed on the apparatus for display 6corresponding to the camera visual points of the plurality of cameras,an apparatus for deflecting light 8 which deflects the two-dimensionalpictures displayed on the apparatus for display 6 into the cameraobserving points of the plurality of cameras 1 in accordance with thecontrol information of the deflection control unit 7 and a device forrecord and replay 3 which records and replays the photographed pictures.The details of each construction will be described as follows.

The Camera

The camera 1 is, for instance, a color TV camera which photographs thetwo-dimensional pictures. A plurality of cameras 1 are arranged againstthe object at the moderate intervals in horizontal direction or invertical direction. The plurality of cameras 1 are arranged at themoderate intervals in horizontal direction or in vertical direction soas to obtain a plurality of two-dimensional pictures at the moderateparallaxes. The reason why the plurality of cameras 1 should be arrangedin horizontal direction is to generate the parallaxes in horizontaldirection. The plurality of cameras 1 should be arranged in verticaldirection so as to generate the parallaxes in vertical direction. Thecameras 1 should be arranged both in horizontal direction and invertical direction so as to generate the parallaxes both in horizontaldirection and in vertical direction.

In FIG. 27, it is supposed that the plurality of cameras from O1 to Onare arranged in horizontal direction. The camera 1 is provided with acamera element which has a predetermined number of picture elements andphotographs the object 10 by the resolution corresponding to the numberof picture elements and outputs the pictures as a plurality of pictureelements.

The Line Division Unit

The line division unit 2 divides the pictures photographed by the camera1 into the number of visual points. The pictures photographed by thecamera 1 are divided into the number of visual points respectively. Forinstance, the original picture of the camera O1 is divided into thenumber of lines corresponding to the number n of the cameras inaccordance with the following Table 1, as shown in FIG. 28.

                  TABLE 1                                                         ______________________________________                                                01 → 01L1, 01L2, 01L3 . . . 01Ln                                       02 → 02L1, 02L2, 02L3 . . . 02Ln                                       03 → 03L1, 03L2, 03L3 . . . 03Ln                                       .  .   .  .  .       .                                                        .  .   .  .  .       .                                                        .  .   .  .  .       .                                                        0n → 0nL1, 0nL2, 0nL3 . . . 0nLn                               ______________________________________                                    

The Time Series Rearrangement Unit

The time series rearrangement unit 4 rearranges the two-dimensionalpictures divided by the line division unit 2 in the time series.

Namely, the original pictures which are divided as mentionedhereinbefore are rearranged and assorted, and the pictures O'1-O'n areformed in accordance with the following Table 2 as shown in FIG. 29.Namely, each of the original pictures O1-On which were obtained fromeach camera 1 and have parallaxes one another is divided into the linesof the number of visual points respectively and each of the picturepieces which were divided is assorted in accordance with the visualpoint order and the time series so that the pictures O'1-O'n of theoriginal number of visual points will be formed.

                  TABLE 2                                                         ______________________________________                                                01L1, 02L2, 03L3 . . . 0nLn → 0'1                                      0nL1, 01L2, 02L3 . . . 0n-1LN → 0'2                                    0n-1L1, 0nL2, 01L3 . . . 0n-2Ln → 0'3                                  .  .    .    .    .  .                                                        .  .    .    .    .  .                                                        .  .    .    .    .  .                                                        02L1, 03L2, 04L3 . . . 01Ln → 0'n                              ______________________________________                                    

The Two-dimensional Picture Display Control Unit

The two-dimensional picture display control unit 5 replays and controlsthe pictures rearranged by the time series rearrangement unit in thetime series order. Namely, the O'1, O'2, O'3 . . . O'n are replayed inaccordance with the order. Generally, the two-dimensional picturecontrol unit 5 is constructed by the CPU of the computer.

The Apparatus for Displaying Two-dimensional Pictures

The apparatus for displaying two-dimensional pictures 6 displays thetwo-dimensional pictures controlled by the two-dimensional picturedisplay control unit 5 in the time series order. LCD (liquid crystaldisplay) is used as the apparatus for displaying two-dimensionalpictures 6.

The LCD has enough number of picture elements to change the lightquantity of the injected light. Namely, the LCD is a transmissiondisplay for changing the quantity of the passing light per pictureelement to replay the two-dimensional pictures. As shown in FIG. 30, thetwo-dimensional picture receives a reference light beamed from the lightsource (L) to be projected to the apparatus for deflecting light 8through the projection optical system 12. The LCD shades the even-orderdiffracted lights including the zero-order light by arranging thepolarizing plates 21 and 22 whose polarizing directions areperpendicular one another before and behind the apparatus for deflectinglight 8. Namely, the LCD converts the incident light into a linearlypolarized light by the first polarizing plate 21, and shades thezero-order light and the even-order diffracted lights which have passedthrough the apparatus for deflecting light 8 by the second polarizingplate 22.

The diffracted lights which have passed through the polarizing plate 22is scattered to the vertical direction by the lenticular lens 20.

The Deflection Control Unit

The deflection control unit 7 deflects and controls the two-dimensionalpictures displayed on the apparatus for displaying two-dimensionalpictures corresponding to the camera visual points of the pluralcameras 1. The deflection control unit 7 changes the voltage applied tothe apparatus for deflecting light 8 to change the phase distribution,that is, the pitch of the interference fringes.

FIG. 31 is a drive control diagram of the VGM apparatus for deflectinglight. The deflection control unit 7 determines the voltage applied toeach picture element by the angle information corresponding to thetwo-dimensional screen to be displayed. Namely, the deflection controlunit 7 refers to the angle-voltage conversion table 14 to lead thevoltage corresponding to the angle information, and generates thevoltage in the apparatus for generating voltage to apply the voltage toeach electrode 16 of the apparatus for deflecting light, after receivingthe synchronizing signal transmitted from the timing generator (timingcontroller) synchronized with the picture display in the apparatus fordisplaying two-dimensional pictures and receiving the angle informationcorresponding to the displayed pictures.

The Apparatus for Deflecting Light

The apparatus for deflecting light 8 deflects the two-dimensionalpictures displayed on the apparatus for display 6 to the virtualaperture 9 corresponding to the camera visual points of the pluralcameras 1 in accordance with the control information of the deflectioncontrol unit. The VGM apparatus for deflecting light is used as theapparatus for deflecting light 8. As shown in FIG. 32 to FIG. 34, theVGM apparatus for deflecting light comprises a liquid crystal 17 whoseanisotropy (Δε) of the permittivity is less than 0, two glass substrates18 into which the liquid crystals 17 is inserted and a transferenceelectrode plate 16 which is arranged among the liquid crystals 17arranged within the two glass substrates 18.

As mentioned hereinbefore, the apparatus for deflecting light 8 makesuse of a phenomenon called Variable Grating Mode (V. G. M.). Thepermittivity difference of the liquid crystal in which the V. G. M.phenomenon occurs is often Δε<0. The representative example of theliquid crystal in which the V. G. M. phenomenon occurs is shown inFIG. 1. The liquid crystal is on the market as N-4 of Merc corporationand is available.

Besides, the plural pairs of transference electrodes 16 are installedplurally on the apparatus for deflecting light 8 in accordance with thenumber of visual points. The interference fringes occur in the liquidcrystal when the voltage is applied to the transference electrodes. InFIG. 32 to FIG. 34, two pairs of electrodes are illustrated, the voltageof V1 is applied among the electrodes of the one side and the voltage ofV2 is applied among the electrodes of the other side, and the relationof V1>V2 is being kept. The spatial frequency of the interferencefringes gets bigger and the space of the fringes gets smaller when thesize of the voltage applied to the electrode is big, and the spatialfrequency of the interference fringes gets smaller and the space of thefringes gets bigger when the size of the voltage applied to theelectrodes is small, like the applied voltage-spatial frequencycharacter diagram shown in FIG. 35. Accordingly, as shown in FIG. 34,the space of the interference fringes of the parts corresponding to theapplied voltage of V2 is bigger than the space of the interferencefringes of the parts corresponding to the applied voltage of V1.

The picture per line is projected into the virtual aperture 9 by thevaried deflections respectively, since each line of the divided picturesis displayed respectively on the picture element of the apparatus fordisplay 6 corresponding to each pair of electrodes 16. The apparatus fordeflecting light is controlled in synchronization state by the timingcontroller 13 so that the apparatus for deflecting light will bedirected to the corresponding deflecting directions, when the pictureO1' is displayed on the apparatus for display 6.

In the embodiment 19, a single unidirectional apparatus for deflectinglight is used and the apparatus has a parallax only in the horizontaldirection. The VGM apparatus for deflecting light has a vertical pictureelement and has a single picture element in the vertical direction. Thenumber of picture elements N in the horizontal direction and the numberof picture elements M of the two-dimensional image display unit in thevertical direction are N:M=1:1 as shown in (A) of FIG. 36, or N:M=1:n(n≧2) as shown in (B) of FIG. 36. It is impossible to see all of thevertical pictures at the same time, since the light beamed from thetwo-dimensional picture display unit is deflected only to the horizontaldirection. Accordingly, as shown in FIG. 30 and FIG. 36, the problem issolved by diffusing the light to the horizontal direction with thelenticular lens 20. Namely, the picture will be projected only to thelower part, if the picture displayed on the lower part of the pictureelement is unchanged. Accordingly, the difference of the picture in theupper and lower directions was eliminated by diffusing the light bothover the lower part and over the upper part equally.

Besides, as shown in FIG. 30, a pair of deflecting plates 21, 22 areinstalled before and behind the apparatus for deflecting light 8. Thezero-order light will be shielded, since the deflecting direction of thepair of deflecting plates 21, 22 is slipped off 90 degrees.

Device for Record and Replay

The device for record and replay 3 records and replays the photographedpictures. There are some cases that the device for record and replay 3executes the following tasks as a device for record:

1 To record each picture which was inputted into the line division unit2 from each of the cameras separately;

2 To record the picture which was divided per line in the line divisionunit; or

3 To record the picture after the picture is rearranged in the timeseries rearrangement unit.

In the device for replay 3 in which the picture recorded in the devicefor record 3 is replayed, the picture should be inputted into the linedivision unit 2 when the picture of the above-mentioned 1 is replayed.Besides, the replayed picture should be inputted into the time seriesrearrangement unit when the picture of the above-mentioned 2 isreplayed. Further, the replayed picture should be inputted into thetwo-dimensional picture display control unit when the picture of theabove-mentioned 3 is replayed.

The Action of the Embodiment 19

The examples in which the stereoscopic display is executed by the devicefor stereoscopic display of the embodiment 19 will be described.

The First Example of Display

First of all, the object is photographed as a two-dimensional picture bya plurality of cameras 1 (O1-On). Then, the picture is inputted into theline division unit 2 to line-divide each picture into the number of thecameras like the above-mentioned Table 1. Then, the divided pictures areassorted in the time series to form O'1-O'n as scene 1. The pictureswill be continued to scene 2, 3 . . . on following the scene 1, sincethese pictures are formed per scene.

The two-dimensional pictures O'1-O'n are replayed and controlled in thetime series order by the two-dimensional picture display control unit tobe displayed on the apparatus for display 6. The picture is deflected tothe virtual apertures S1-Sn in the apparatus for deflecting lightcontrolled by the deflection control unit 7, making the two-dimensionalpicture displayed on the apparatus for display 6 correspond to thecamera visual point of the plurality of cameras. Namely, thetwo-dimensional picture projected into the VGM apparatus for deflectinglight from LCD by the optical system is deflected to the wished-forvirtual aperture positions, in accordance with the pitch of therefractive index distribution which occurred in the apparatus fordeflecting light 8.

FIGS. 37(A)-(D) are the examples of the method for scanning light whenthe stereoscopic display is executed by using the divided pictures. InFIG. 37, the deflecting system has a plurality of picture elements, andgives the varied phase distributions to each of the picture elements andexecutes the deflection against the wished-for virtual apertures byvarying the voltage applied to the electrode installed on each of thepicture elements. In the case of this method, the deflection should beexecuted per line against all of the virtual apertures. In this case,the deflecting system 8 has a plurality of picture elements, andexecutes the scanning against the deflecting system picture elementsM_(L1), M_(L2), . . . M_(Ln) and the virtual apertures S₁, S₂, . . .S_(n) in the following order during the time from t₁ to T_(n).

t₁ M_(L1) →S₁, M_(L2) →S₂ . . . M_(Ln) →S_(n) FIG. 37(A)

t₂ M_(L1) →S₂, M_(L2) →S₃ . . . M_(Ln) →S₁ FIG. 37(B)

t₃ M_(L1) →S₃, M_(L2) →S₄ . . . M_(Ln) →S₂ FIG. 37(C)

t_(n) M_(L1) →S_(n), M_(L2) →S₁ . . . M_(Ln) →S_(n-1) FIG. 37(D)

(M_(L1) →S₁ means that the picture element of M_(L1) executes thedeflection against the virtual aperture S₁.)

In the case of this method for deflection, the deflection is executedsynchronizing with the writing per line.

In this method, the picture is displayed in order by dividing onepicture into a plurality of lines. Accordingly, the fatigue of theobserver's eyes can be reduced by these actions, compared with the casethat the whole picture is always shown to the observer so as to displaythe picture (the apparatus for display can never be darkened wholly),even though the picture which can be seen from the observer is part ofthe whole pictures.

Although the picture which was divided in the time series and rearrangedin the time series is replayed by the time series in order of O'1-O'nand is projected in the time series to the observing points S1-Sncorresponding to the virtual apertures S1-Sn, the pictures of O'1-O'nwill be seen simultaneously to be formed as stereoscopic images, sincethe after images remain in human's eyes.

By the way, as shown in FIG. 39, the odd-order diffracted light and theeven-order diffracted light occur in the outgoing light side, and theplane of polarization is perpendicular in the odd-order diffracted lightand the even-order diffracted light, when the linearly polarized lightis injected into the VGM apparatus for deflecting light. As shown inFIG. 30 and FIG. 38, the even number order diffracted light can beshaded by placing the VGM apparatus for deflecting light 8 between thetwo polarizing plates 21, 22 which are perpendicular one another.Namely, the incident light is converted into the linearly polarizedlight by the first polarizing plate 21 to shade the even-orderdiffracted light which has passed through the VGM apparatus fordeflecting light by the second polarizing plate 22. For this reason, asshown in FIG. 38 and FIG. 40, the transmitted light (zero-order light)can be shield. Further, the two polarizing plates can shade thezero-order light substantially, if it is crossed in the angle of 90degrees ±10.

The Second Example of Display

FIG. 41 indicates a case that the apparatus for deflecting light 8 has asingle picture element. Namely, FIG. 41 indicates a case that only onepair of electrodes are arranged in the apparatus for deflecting light 8and the whole apparatus for deflecting light is deflected to only thefixed directions equally.

The picture is displayed on the apparatus for displaying two-dimensionalpicture 6, when the picture is inputted from the two-dimensional pictureinput unit. The voltage of the apparatus for deflecting light 8 iscontrolled by the timing controller 13 synchronizing with the picturedisplay on the apparatus for displaying two-dimensional picture 6 sothat the degree of deflection will be controlled.

In this case, the deflected pictures are converted into the parallelrays, and they can not be converged in that condition, since each angleof polarization for DL1-DLN of the apparatus for displayingtwo-dimensional picture 6 is the same in the apparatus for deflectinglight 8 which has a single picture element. Accordingly, the deflectedpictures are converged into the wished-for virtual aperture by using thelens 19 in front of the apparatus for deflecting light 8.

Elimination and Control of Display

In case of the method for deflection according to the above-mentionedfirst and second example of display, the deflection is executedsynchronizing with the writing of the whole two-dimensional picture.However, the elimination time of the display screen should be providedin the deflection control unit 7 before rewriting the screen and thedeflection should be stopped during that time, in order to prevent theafter image of the picture which was deflected to S_(k) from being seenin the position of S_(k+1), when the deflection is moved from onevirtual aperture S_(k) to the next virtual aperture S_(k+1). In thiscase, in the two-dimensional image display control unit 5, the intensityof the apparatus for display 6 should be darkened extremely so that theobserver will not feel the after image.

The writing of the screen-and the deflection should be restarted aftereliminating one screen. FIG. 42 is a timing chart of a method fordeflection. First of all, the screen should be eliminated afterdisplaying the image of S1O1 on the virtual aperture S1. After that, thepicture of S1O2 should be displayed on the virtual aperture S2 and thepicture of S1On should be displayed on the virtual aperture Sn tocomplete the picture display of scene 1. Then, the images S2O1 . . .S2On of scene 2 should be displayed.

The Third Example of Display

It is also possible to execute the stereoscopic display without dividingthe pictures by using the device for stereoscopic display of theabove-mentioned construction.

However, in this case, the line division unit 2 and the time seriesrearrangement unit 4 are not needed and only have a two-dimensionalpicture input unit 30 which inputs the inputted pictures in the timeseries.

The example is shown in FIGS. 43(A)-(C). In FIGS. 43(A)-(C), theapparatus for deflecting light 8 has a plurality of picture elements,and gives the varied phase distributions to each of the picture elementsand executes the deflection against the wished-for virtual aperture byvarying the voltage applied to the electrodes installed on each pictureelement.

The FIGS. 43(A)-(C) is one of the embodiments of the method fordeflection of the apparatus for deflecting light 8. In this method, thedeflection is executed only to one virtual aperture in one time t=t_(n),and the deflection is executed in order from the virtual aperture S1 toSn, namely, in order from FIGS. 43(A) to (C), following from t=t_(n+1)to t=t_(n+k). In this case, the picture (one of O'1, O'2, O'3 . . .O'_(n)) corresponding to the deflecting position is displayed on thetwo-dimensional picture display unit. Namely, the two-dimensionalpicture inputted from the camera 1 is arranged in the time series as itis, and is displayed on the apparatus for displaying two-dimensionalpicture to be deflected to the virtual aperture as it is.

The Effect of the Embodiment 19

As mentioned hereinbefore, the mechanically movable parts are not neededfor displaying stereoscopic pictures, since the VGM apparatus fordeflecting light is used in the embodiment 19. Besides, the angle ofdeflection by the VGM apparatus for deflecting light is enough, and itis possible to execute the stereoscopic display sufficiently.

The visual region of 30 degrees or so is desirable as a visual region ofthe apparatus for stereoscopic display. When the light of wave length λis injected into the diffraction grating of the pitch d, their relationto the angle of diffraction θ will be as follows,

    d·Sin θ=n·λ

and d should be 1.26 μm when λ=633 nm, in order to obtain a primarylight diffraction angle of 30 degrees. Namely, the picture element whosepitch is 1 μm (1000 spatial frequencies/mm) or so is needed forobtaining a deflecting system of deflection angle 30 degrees by theconventional LCD. On the other hand, in the VGM apparatus for deflectinglight of the present invention, the spatial frequency is determined bythe applied voltage, not by the picture element pitch. Accordingly, itis possible to obtain an apparatus for stereoscopic display which has adesirable range of view easily.

EMBODIMENT 20 Device for Stereoscopic Display

FIG. 44 is an embodiment of the case in which a plurality of onedirectional apparatuses for deflecting light are used. Thetwo-dimensional picture projected from the apparatus for displayingtwo-dimensional picture 6 is deflected to the vertical direction by theVGM apparatus for deflecting light for vertical direction 8-1 which hasa horizontal picture element, and is deflected to the horizontaldirection by the VGM apparatus for deflecting light for horizontaldirection 8-2 which has a vertical picture element. By these actions,the stereoscopic picture which has a parallax both in upper directionand in lower direction can be displayed.

EMBODIMENT 21 Device for Stereoscopic Display

In the control of the apparatus for deflecting light of theabove-mentioned embodiments 19 and 20, it is necessary to change thephase distribution according to the angle information of the deflection.Namely, it is desirable that the stereoscopic display is executedwithout calculating the phase distribution as follows, even though it isalso possible to calculate the phase distribution in accordance with theangle information and control the apparatus for deflecting light.

Preparation of Phase Distribution Storage Tables

A phase distribution (interference fringes) which brings on a lightdeflection determined per picture which varies in visual directions isstored as a table data previously in the phase distribution storagetable shown in FIG. 48 and FIG. 52. The deflection control unit 7 refersto the data stored in the phase distribution storage table to controlthe phase distribution of the apparatus for deflecting light.

Further, Φ11,11, Φ11,12, . . . Φ11,mn correspond to the phase of eachinterference fringe in FIG. 48. Similarly, Φ11,1, Φ11,2, . . . Φ11,ncorrespond to the phase of each interference fringe in FIG. 52.

The preparation of the data stored in the phase distribution storagetable will be described as follows.

(A) Calculation of Phase Distribution

First of all, the principle of hologram will be described. The hologramcan be obtained by two luminous interference of the laser light (objectlight) which is scattered from the object dividing one laser light intotwo laser lights and applying the laser light of one side to the object,and the other laser light (reference light). Hereupon, the exposureintensity I_(H) of the hologram will be as follows, if the wave front ofthe reference light is R·exp (jφ_(r)) and the wave front of the objectlight is O·exp (jφ_(o)).

    I.sub.H =R.sup.2 +O.sup.2 +2·R·O·cos (φ.sub.o -φ.sub.r)                                (1)

The amplitude and the phase which are in proportion to the exposureintensity of the formula (1) changes in the hologram, when the hologramis developed. Such spatial light modulation element as a liquid crystaldevice which is capable of changing the amplitude and the phase of thelight should be used to prepare the hologram electrically.

The hologram can be replayed by injecting the wave front which is thesame as the reference light into the hologram prepared in theabove-mentioned way. The transmitted light T from the hologram will beas follows when the third term of the right side is considered, sinceonly the third term of the right side out of the exposure intensityI_(H) of the formula (1) contributes to the replay of the object light.

    T=I.sub.H ·R·exp (jφ)∞2·O·cos (φ.sub.o -φ.sub.r)·exp (φ.sub.r)=O·exp (jφ.sub.o)+O·exp {-j (φ.sub.o -2·φ.sub.r)}(2)

Hereupon, the first term of the right side of the formula (2) indicatesthat the wave front from the object was replayed. The second term of theright side indicates a conjugated wave of the object light.

As shown in the above-mentioned description of the principle, in thecalculation of the phase distribution of the hologram, only the thirdterm of the right side of the formula (1) should be calculated.

FIG. 45 indicates a calculation principle of the phase distribution inholographic stereogram. The light intensity R can be ignored and can betreated as phase φ r=0, since the intensity of the plane wave does notchange according to the locations, when the reference light isconsidered as a plane wave. The coordinate value of Z axis direction ofthe two-dimensional picture is fixed in Zi.

The exposure intensity I_(H) of Q point which will become thecoordinates (X_(hi), Y_(hi)) of the holographic stereogram will be asfollows, when the intensity (degree of scatter) of one sampling point Pwhich has coordinates (X_(i), Y_(i)) within the two-dimensional picturesis regarded as I_(i).

    I.sub.H =Σ{(I.sub.i /r.sub.i) cos (k·r.sub.i)}(3)

excepting that k is the wave number of the laser light.

    r.sub.i =√ {(X.sub.i -X.sub.hi).sup.2 +(Y.sub.i -Y.sub.hi).sup.2 +Z.sub.i.sup.2 }                                          (4)

The calculation of the formula (3) and (4) should be executed extendingover the whole region of the holographic stereogram, since the lightbeamed from each picture element of the two-dimensional pictures reachesthe whole hologram.

(B) Phase Calculation of Image Hologram which has a Horizontal Parallaxand a Vertical Parallax

FIG. 46 is a descriptive diagram indicating a deflecting function of anapparatus for deflecting light for stereoscopic display which has ahorizontal parallax and a vertical parallax. The apparatus fordeflecting light 8 arranges M×N pieces of one picture element portionphase display unit in total corresponding to one picture element of thetwo-dimensional pictures, M pieces in vertical direction and N pieces inhorizontal direction. Hereupon, the picture element corresponding tooptional one picture element portion phase display unit will berepresented in P_(ij), if the horizontal direction is represented in jand the vertical direction is represented in i.

The virtual apertures are arranged in a position which will be a visibleregion to the apparatus for deflecting light 8. The virtual aperturearranges n×m pieces in total, n pieces in horizontal direction and mpieces in vertical direction. Hereupon, the optional virtual apertureregion will be represented in S_(kL), if the horizontal direction isrepresented in L and the vertical direction is represented in k.

Hereupon, the one picture element portion phase display unit on theupper right corner of the apparatus for deflecting light 8 indicates adeflection state of the display light beamed from the correspondingpicture element P_(IN), and the light beamed from the correspondingpicture element P_(IN) will be deflected to the regions S₁₁ -S_(mn) ofall virtual apertures.

FIG. 47 indicates a method for calculating a phase distribution whichrealizes the above-mentioned deflection functions. The method forcalculating the phase distribution in the one picture element portionphase display unit of the corresponding picture element P_(ij) isindicated by taking the relation between one virtual aperture 48 and theregion S_(kL) for instance.

First of all, in FIG. 47, a plurality of virtual point light sources 50should be arranged on the virtual aperture 48 in the horizontal andvertical direction. The virtual reference light 52 should be set up atthe same time. The phase distribution should be calculated per pictureelement for phase display 54 which organizes the one picture elementportion phase display unit 46 by the above-mentioned formula (3)and (4)among the all virtual point light sources 50 in this state.

Hereupon, as shown in FIG. 49, a plurality of two-dimensional data G₁₁-G_(mn) which regard the virtual aperture regions S₁₁ -S_(mn) as visualpoints are prepared to display the data in order division. For thisreason, the virtual aperture shown in FIG. 46 changes temporallyfollowing the switching of the two-dimensional picture data G₁₁ -G_(mn)in the horizontal and the vertical direction. Accordingly, in thecalculation of the phase distribution of FIG. 47, the virtual apertureregion whose position changes temporally following the two-dimensionalpictures G₁₁ -G_(mn) is calculated.

Accordingly, the phase distribution φ_(ij), 11 -φ_(ij), mn will becalculated in connection with the optional corresponding picture elementO_(ij), in order to deflect the light beamed from the picture element tothe virtual apertures 48 of S₁₁ -S_(mn) which vary corresponding to thetwo-dimensional picture display by the time division.

For this reason, the phase distribution data used by the time divisiondisplay per corresponding picture element will be stored in the phasedistribution table of the present invention as shown in FIG. 48.

(C) Phase Calculation of Image Hologram which has a Horizontal Parallax

FIG. 50 is a descriptive diagram indicating a deflecting function of theapparatus for deflecting light 8 for stereoscopic display of the presentinvention which has a horizontal parallax. In FIG. 50, the apparatus fordeflecting light 8 arranges the picture elements which are lengthy inthe vertical direction. On the other hand, the virtual aperture 48arranges the n pieces in the horizontal direction as a stripe regionwhich is lengthy in the vertical direction. Hereupon, the optionalvirtual aperture region will be represented in S₁, if the horizontaldirection is represented in 1.

Hereupon, the one picture element portion phase display unit 46 on theright upper corner of the apparatus for deflecting light 8 indicates adeflection state of the display light beamed from the correspondingpicture element P_(IN), The light beamed from the corresponding pictureelement P_(IN) will be deflected to the regions S₁ -S_(n) of all virtualapertures as shown in FIG. 50.

FIG. 51 indicates a method for calculating phase distribution whichrealizes a deflecting function shown in FIG. 50. and indicates themethod for calculating phase distribution in the one picture elementportion phase display unit 46 of the corresponding picture elementP_(ij) by taking the relation between one virtual aperture 48 and theregion S₁ for instance.

First of all, also in case of FIG. 50, a plurality of virtual pointlight sources 50 should be arranged on the virtual aperture 48 in thehorizontal and the vertical direction. The virtual reference light 52should be set up at the same time. The phase distribution should becalculated per picture element for phase display 54 which organizes theone picture element portion phase display unit 46 by the above-mentionedformula (3) and (4) among the all virtual point light sources 50 in thisstate.

Hereupon, as shown in FIG. 53, a plurality of two-dimensional picturedata G₁ -G_(n) which regard the virtual aperture regions S₁ -S_(n) asvisual points are prepared to display the data in time division. Forthis reason, the virtual aperture shown in FIG. 50 changes temporallyfollowing the switching of the two-dimensional picture data G₁ -G_(n) inthe horizontal direction. Accordingly, in the calculation of the phasedistribution of FIG. 47, the virtual aperture region whose positionchanges temporally following the two-dimensional pictures G_(1-G) _(n)is calculated.

Accordingly, the phase distribution Φ_(ij),-Φ_(ij), mn will becalculated in connection with the optional corresponding picture elementP_(ij), in order to deflect the light beamed from the picture element tothe virtual apertures 48 of S₁ -S_(mn) which vary corresponding to thetwo-dimensional picture display by the time division.

For this reason, the phase distribution data used by the time divisiondisplay per corresponding picture element will be stored in the phasedistribution table of the present invention which has a horizontalparallax as shown in FIG. 52.

(D) Phase Calculation of Image Holograph when Picture is Divided

FIG. 54 is a descriptive diagram indicating a deflecting function of anapparatus for deflecting light 8 of the present invention which executesthe stereoscopic display which has a horizontal parallax using thedivided pictures.

In FIG. 54, the apparatus for deflecting light 8 arranges the pictureelements which are lengthy in the vertical direction. On the other hand,the virtual aperture 48 arranges n pieces in the horizontal direction asa stripe region which is lengthy in the vertical direction. Hereupon,the optional virtual aperture region will be represented in S₁, if thehorizontal direction is represented in 1.

Hereupon, the two-dimensional pictures are divided in the verticaldirection to be converted into the horizontal stripe pictures. For thisreason, the one picture element portion phase display unit 46 on theright upper corner on the apparatus for deflecting light 8 indicatesthat the light beamed from the corresponding picture element P_(1N) isdeflected to the regions S₁₁ -S_(1n) of the uppermost line of thevirtual aperture on the basis of the picture division. Similarly, thelight is deflected to the regions of the second line of the virtualaperture 48 in connection with the second line of the apparatus fordeflecting light 8. As a result, the one picture element portion phasedisplay unit 46 arranged in the vertical direction of the apparatus fordeflecting light 8 will be deflected to the same direction wholly, andwill own the same phase distribution.

Accordingly, the corresponding picture elements will be represented inP₁ -O_(N) making them into one in the vertical direction, since aplurality of phase distributions of one picture element portion phasedisplay units 46 arranged in the vertical direction of the apparatus fordeflecting light 8 can be treated as one phase distribution.

FIG. 55 indicates a method for calculating a phase distribution whichrealizes a deflecting function shown in FIG. 54, and indicates themethod for calculating the phase distribution in the one picture elementportion phase display unit 46 of the corresponding picture element P_(j)by taking the relation between one virtual aperture 48 and the region S₁for instance.

In case of FIG. 55, the vertical horizontal plane 56 should be set onthe one picture element portion display unit 46 and the virtual aperture48, and a plurality of virtual point light sources 50 should be arrangedon the virtual aperture 48 along the horizontal plane 56 in thehorizontal direction. The virtual reference light should be set up atthe same time. The phase distribution should be calculated per pictureelement for phase display 54 which organizes the one picture elementportion phase display unit 46 by the above-mentioned formula (3) and (4)among the all virtual point light sources 50 in this state.

Hereupon, the two-dimensional picture data is the same as FIG. 54 and aplurality of two-dimensional picture data G₁ -G_(n) which regard thevirtual aperture regions S₁ -S_(n) as visual points are prepared todisplay the data in time division. For this reason, the virtual aperture48 shown in FIG. 54 changes temporally following the switching of thetwo-dimensional picture data G₁ -G_(n) in the horizontal direction.Accordingly, in the calculation of the phase distribution of FIG. 47,the virtual aperture region whose position changes temporally followingthe two-dimensional pictures G₁₁ -G_(mn) is calculated.

Accordingly, the phase distribution Φ_(ij),-Φ_(ij), mn will becalculated in connection with the optional corresponding picture elementP_(ij), in order to deflect the light beamed from the picture element tothe virtual apertures 48 of S₁ -S_(n) which vary corresponding to thetwo-dimensional picture display by time division.

For this reason, the phase distribution data used by the time divisiondisplay per corresponding picture element will be stored in the phasedistribution table of the present invention which has a horizontalparallax as shown in FIG. 56.

In the stereoscopic display of the present invention using the phasedistribution of the division two-dimensional increase, as shown in FIG.54, the deflecting direction in the vertical direction will not bechanged at all, even if the two-dimensional pictures which vary in thevisual directions are, and the deflecting direction in the horizontaldirection will be changed per two-dimensional picture. For this reason,the light is not scattered to the vertical direction and should befurther enlarged optically to the vertical direction when thestereoscopic image is replayed.

Accordingly, as shown in FIG. 57, for instance, the lenticular lens 112should be provided as an optical element which has a vertical visibleregion enlargement function following the apparatus for deflecting light8 and should be scattered to the vertical direction to create a visibleregion 45. This procedure is mentioned above.

EMBODIMENT 22 Device for Stereoscopic Display

FIG. 58 is a schematic diagram of a record and replay system forrealizing the present invention. The two-dimensional picturesphotographed by a plurality of cameras are compressed by the datacompression unit 601 with the angle information according to theposition of the camera to be recorded in the recorder 602 or to betransmitted by the transmitter. The two-dimensional picture is recordedin such record media as a magnetic tape, when it is recorded. Thetwo-dimensional picture is transmitted thorough such communication mediaas a communication network when it is transmitted.

The data which was replayed or transmitted is extended by the dataextension unit 603 with the angle information to be inputted into thecalculator. In the interpolated picture generating unit 604 of thecalculator, the parallax pictures of the number to be displayed on thebasis of the angle information of each picture are calculatedinterpolating and such operations as enlargement, reduction, replacementof lines are added by the editing unit 605 as occasion demands to bewritten into the frame buffer with the numbers corresponding to theangle information. The deflection control unit 7 controls the apparatusfor deflecting light so that the wished-for deflection will be executedby the apparatus for controlling voltage 607. The readout circuit 606reads the two-dimensional picture data corresponding to the deflectionangle by the frame buffer and outputs it to the apparatus for display.

As mentioned hereinbefore, the stereoscopic display should be executedby displaying the two-dimensional pictures corresponding to the angle inthe predetermined field of range respectively.

The Effect of Device for Stereoscopic Display of the Present Invention

In the present invention, the device for stereoscopic display can dowithout mechanically movable parts, the device is not influenced by themechanical resonance, the accuracy of the stereoscopic display isimproved and the maintenance is easily executed, since an apparatus fordeflecting light in which the liquid crystal whose anisotropy (Δε)ofpermittivity is less than 0 are caught among the pair of electrodesfacing one another is used as beam deflection means.

Besides, the device for stereoscopic display comprises a line divisionunit which divides the pictures photographed by the cameras into thenumber of visual points, a time series rearrangement unit whichrearranges the two-dimensional pictures divided by the line divisionunit in the time series, and a two-dimensional picture display controlunit which replays and controls the two-dimensional pictures rearrangedby the time series rearrangement unit in the time series order. Thefatigue of the observer's eyes can be mitigated by the beam deflectionmeans, since the beam deflection means displays the partial pictures bydeflecting the two-dimensional pictures displayed in the two-dimensionalpicture display means to the virtual aperture corresponding to thecamera visual point of the plurality of cameras.

The beam deflection means is capable of obtaining the horizontal and thevertical stereoscopic pictures by deflecting the pictures to thehorizontal direction or by deflecting the pictures to the verticaldirection.

The vertical pictures can be seen equally by installing the lightdiffusion means for the vertical direction when the beam deflectionmeans deflects only to the horizontal direction.

Besides, it became possible to execute the stereoscopic display quickly,since the time necessary for calculating the phase distribution can bereduced when the deflection control unit which controls the beamdeflection means refers to the phase distribution table in which thephase distribution data is stored to determine the deflection angleaccording to the beam deflection means.

The zero-order light can be shaded by arranging a pair of polarizingplates in which the deflecting directions are crossed in the angle of 90degrees ±10 before and behind the beam deflection means.

The after image of the last display can be cut and the clearstereoscopic display can be executed, since the elimination time of thelast display screen is provided before rewriting the screen in thedeflection control unit and the deflection is stopped during the time,when the deflection is moved from one virtual aperture to the nextvirtual aperture by the beam deflection means.

At that time, the stereoscopic display can be clearer by darkening theintensity of the picture display according to the two-dimensionalpicture display means.

Then, the stereoscopic picture communication system which comprises atransmission side for transmitting a plurality of two-dimensionalpictures which vary in visual directions through the communicationnetwork and a receiving side for receiving the transmittedtwo-dimensional pictures, displays the received two-dimensional picturesin the two-dimensional picture display means and displays thestereoscopic picture in a remote location by deflecting the light beamedfrom the picture element which organizes the pictures of the picturedisplay means in the beam deflection means corresponding to the variedvisual directions can be realized.

What is claimed is:
 1. A device for reading information, comprising:(a)at least one apparatus for deflecting light having a pair oftransference electrodes arranged facing one another, and a liquidcrystal inserted between said transference electrodes, thereby forming,when a voltage is applied between said transference electrodes, parallelstripes which function as a diffraction grating at a pitch correspondingto a value of the voltage; (b) a drive circuit for applying a voltagebetween said transference electrodes of said apparatus for deflectinglight, where a value of said voltage changes as time elapses; (c) alight source beaming a light to be incident onto said apparatus fordeflecting light at an incident angle substantially equal to adiffraction angle of one of a plurality of beams of diffracted lightemitted from said apparatus for deflecting light; (d) an apparatus fordetecting light which detects a reflected light when scanning lightdiffracted by said apparatus for deflecting light is reflected in aninformation medium; and (e) shading means for cutting off azero-dimensional diffracted light of the apparatus for deflecting lightinstalled on the outgoing light side of said apparatus for deflectinglight.
 2. A device for reading information according to claim 1,whereinthe information medium is a bar code.
 3. A device for readinginformation, comprising:(a) at least one apparatus for deflecting lighthaving a pair of transference electrodes arranged facing one another,and a liquid crystal inserted between said transference electrodes,thereby forming, when a voltage is applied between said transferenceelectrodes, parallel stripes which function as a diffraction grating ata pitch corresponding to a value of the voltage; (b) a drive circuit forapplying a voltage between said transference electrodes of saidapparatus for deflecting light, where a value of said voltage changes astime elapses; (c) a light source beaming a light to be incident ontosaid apparatus for deflecting light at an incident angle substantiallyequal to a diffraction angle of one of a plurality of beams ofdiffracted light emitted from said apparatus for deflecting light; (d) acondensing optical element installed on one of an incident side and anemitting side of said apparatus for deflecting light; (e) changing meansfor changing a distance along a light axis from the light source to thecondensing optical element; and (f) an apparatus for detecting lightwhich detects a reflected light when scanning light diffracted by saidapparatus for deflecting light is reflected in an information medium. 4.A device for reading information, comprising:(a) at least one apparatusfor deflecting light having a pair of transference electrodes arrangedfacing one another, and a liquid crystal inserted between saidtransference electrodes, thereby forming, when a voltage is appliedbetween said transference electrodes, parallel stripes which function asa diffraction grating at a pitch corresponding to a value of thevoltage; (b) a drive circuit for applying a voltage between saidtransference electrodes of said apparatus for deflecting light, where avalue of said voltage changes as time elapses; (c) a light sourcebeaming a light to be incident onto said apparatus for deflecting lightat an incident angle substantially equal to a diffraction angle of oneof a plurality of beams of diffracted light emitted from said apparatusfor deflecting light; (d) a condensing optical element installed on anincident side or an emitting side of said apparatus for deflectinglight; (e) a half mirror which reflects light emitted from thecondensing optical element in a direction away from the apparatus fordeflecting light; (f) a second condensing optical element whichconverges the light reflected by the half mirror; (g) a reflectingmember which reflects light emitted from the second condensing opticalelement to make it pass through the second condensing optical elementand the half mirror and incident onto the apparatus for deflectinglight; (h) a variable mechanism which changes a distance along a lightaxis from the second condensing optical element to the reflectingmember; and (i) an apparatus from detecting light which detects areflected light when scanning light diffracted by said apparatus fordeflecting light is reflected in an information medium.
 5. A device forreading information, comprising:(a) an apparatus for deflecting lighthaving a pair of transference electrodes arranged facing one another,and a liquid crystal inserted between said transference electrodes,thereby forming, when a voltage is applied between said transferenceelectrodes, parallel stripes which function as a diffraction grating ata pitch corresponding to a value of the voltage; (b) a condensingoptical element installed on an incident side or an emitting side of thesaid apparatus for deflecting light; (c) a drive circuit for applying avoltage between said transference electrodes of said apparatus fordeflecting light, where a value of said voltage changes as time elapses;(d) a light source for beaming a light to be incident on said apparatusfor deflecting light; (e) changing means for changing a distance along alight axis from the light source to the condensing optical element; (f)a polarizer which is arranged so that the polarizing direction issubstantially orthogonal to a polarizing direction of the incident lightof said apparatus for deflecting light, and is installed on the outgoinglight side apparatus for deflecting light; and (g) an apparatus fordetecting light which detects a reflected light when scanning lightdiffracted by said apparatus for deflecting light is reflected in aninformation medium.
 6. A device for reading information, comprising:(a)an apparatus for deflecting light having a pair of transferenceelectrodes arranged facing one another, and a liquid crystal insertedbetween said transference electrodes, thereby forming, when a voltage isapplied between said transference electrodes, parallel stripes whichfunction as a diffraction grating at a pitch corresponding to a value ofthe voltage; (b) a condensing optical element installed on one of anincident side and an emitting side of the said apparatus for deflectinglight; (c) a half mirror which reflects light emitted from thecondensing optical element in a direction away from the apparatus fordeflecting light; (d) a second condensing optical element whichconverges the light reflected by the half mirror; (e) a reflectingmember which reflects light emitted from the second condensing opticalelement to make it pass through the second condensing optical elementand the half mirror and incident onto the apparatus for deflectinglight; (f) a variable mechanism which changes a distance along a lightaxis from the second condensing optical element to the reflectingmember; (g) a drive circuit for applying a voltage between saidtransference electrodes of said apparatus for deflecting light, where avalue of said voltage changes as time elapses; (h) a light source forbeaming a light to be incident on said apparatus for deflecting light;(i) a polarizer which is arranged so that the polarizing direction issubstantially orthogonal to a polarizing direction of the incident lightof said apparatus for deflecting light, and is installed on the outgoinglight side apparatus for deflecting light; and (j) an apparatus fordetecting light which detects a reflected light when scanning lightdiffracted by said apparatus for deflecting light is reflected in aninformation medium.